C Programming Code Examples

/* Bricks game in C */ #include <iostream.h> #include <conio.h> #include <ctype.h> # include <process.h> # include <dos.h> # include <stdlib.h> # include <graphics.h> # include <stdio.h> # define NULL 0 # define YES 1 # define NO 0 #define ESC 0x1b /* Define the escape key */ int MaxX, MaxY, MidX, MidY ; int bri[5][20] ; int GraphDriver; /* The Graphics device driver */ int GraphMode; /* The Graphics mode value */ double AspectRatio; /* Aspect ratio of a pixel on the screen*/ int MaxXX, MaxYY; /* The maximum resolution of the screen */ int MaxColors; /* The maximum # of colors available */ int ErrorCode; /* Reports any graphics errors */ struct palettetype palette; /* Used to read palette info*/ // Initialize the graphics mode void Initialize(void); // Display the last screen of bricks void SayGoodbye(void); // Establish the main window for the demo void MainWindow(char *header); // Display the message Press any key to continue at last screen void StatusLine(char *msg); // Draws a boarder line at last screen void DrawBorder(void); // Changes the text style void changetextstyle(int font, int direction, int charsize); // Welcome screen of bricks game mainscreen(); // Instruction messages of bricks game screen(); // To display the bricks (in square box) and paddles in rectangle form and bulbs rounded form bricks(); // Delete a bricks when bulb hit it delbrick(int,int); // Echoes different musics bell(int); int graphmode = CGAHI, graphdriver = CGA, level; main () { union REGS ii, oo ; int BallX, BallY, Base1, Base2, dx = 1, dy = -1, OldX, OldY ; int totallayer[5] = { 10, 20, 30, 40, 50 }, max = 50, layer = 4 ; int i, flag = 0, speed = 25, score = 0, chance = 4, areareq ; char *m1, *m2 ; /* Function to initialise the graphics mode */ initgraph ( &graphdriver, &graphmode, "c:\tc\bgi " ) ; mainscreen(); initgraph ( &graphdriver, &graphmode, "c:\tc\bgi " ) ; /* get the maximum value of x and y coordinates of the screen */ MaxX = getmaxx() ; MaxY = getmaxy() ; /* finding the center of the screen */ MidX = MaxX / 2 ; MidY = MaxY / 2 ; /* create opening screen and accept the level of the player's */ level = screen() ; /* assign the speed to ball as per the level chosen */ switch ( level ) { case 'M' : case 'm' : speed = 15 ; break ; case 'F' : case 'f' : speed = 10 ; } /* draw the four layer of bricks, the paddle and the ball */ rectangle ( 0, 0, MaxX, MaxY - 12 ) ; bricks() ; rectangle ( MidX - 25, MaxY - 7 - 12, MidX + 25, MaxY - 12 ) ; floodfill ( MidX, MaxY - 1 - 12, 12 ) ; circle ( MidX, MaxY - 13 - 12, 12 ) ; floodfill ( MidX, MaxY - 10 - 12, 12 ) ; /* memory allocation for storing the image of the paddle */ areareq = imagesize ( MidX - 12, MaxY - 18, MidX + 12, MaxY - 8 ) ; m1 =((char*) malloc ( areareq )) ; /* memory allocation for storing the image of the ball */ areareq = imagesize ( MidX - 25, MaxY - 7, MidX + 25, MaxY - 1 ) ; m2 =((char *) malloc ( areareq ) ); /* if unable to alloacte the memory */ if ( m1 == NULL || m2 == NULL ) { puts ( "Not Enough memory!!" ) ; exit ( 1 ) ; } /* image of the paddle and the ball is stored into allocated memory */ getimage ( MidX - 12, MaxY - 7 - 12 - 12 + 1, MidX + 12, MaxY - 8 - 12, m1 ) ; getimage ( MidX - 25, MaxY - 7 - 12, MidX + 25, MaxY - 1 - 12, m2 ) ; /* store current position of the paddle and ball */ Base1 = MidX - 25 ; Base2 = MaxY - 7 - 12 ; BallX = MidX - 12 ; BallY = MaxY - 7 - 12 + 1 - 12 ; /* display balls remaining ( initially 3 ) */ gotoxy ( 45, 25 ) ; cout<< "Balls :" ; for ( i = 0 ; i < 3 ; i++ ) { circle ( 515 + i * 35, MaxY - 5, 12 ) ; floodfill ( 515 + i * 35, MaxY - 5, 12 ) ; } /* display starting score */ gotoxy ( 1, 25 ) ; cout<< "Score: "; gotoxy(16,25); cout<<score; /* select font and alignment for displaying text */ settextjustify ( CENTER_TEXT, CENTER_TEXT ) ; changetextstyle ( GOTHIC_FONT, HORIZ_DIR, 4 ) ; while ( 1 ) { flag = 0 ; /* saving current x and y coordinates of the ball */ OldX = BallX ; OldY = BallY ; /* update ballx and bally to move the ball in correct direction */ BallX = BallX + dx ; BallY = BallY + dy ; /* according to the position of ball the layer of bricks is determined */ if ( BallY > 40 ) { max = 50 ; layer = 4 ; } else { if ( BallY > 30 ) { max = 40 ; layer = 3 ; } else { if ( BallY > 20 ) { max = 30 ; layer = 2 ; } else { if ( BallY > 10 ) { max = 20 ; layer = 1 ; } else { max = 10 ; layer = 0 ; } } } } /* if the ball hits the right boundary, move it to the left */ if ( BallX > ( MaxX - 24 - 1 ) ) { bell ( 5 ) ; BallX = MaxX - 24 - 1 ; dx = -dx ; } /* if the ball hits the left boundary, move it to the right */ if ( BallX < 1 ) { bell ( 5 ) ; BallX = 1 ; dx = -dx ; } /* if the ball hits the top boundary, move it down */ if ( BallY < 1 ) { bell ( 5 ) ; BallY = 1 ; dy = -dy ; } /* if the ball is in the area of the bricks */ if ( BallY < max ) { /* if there is no brick at the top of the ball */ if ( bri[layer][ ( BallX + 10 ) / 32 ] == 1 ) { /* if the ball touches a brick */ for ( i = 1 ; i <= 6 ; i++ ) { /* check whether there is a brick to the right of the ball */ if ( bri[layer][ ( BallX + i + 10 ) / 32 ] == 0 ) { /* if there is a brick */ BallX = BallX + i ; flag = 1 ; break ; } /* check whether there is a brick to the left of the ball */ if ( bri[layer][ ( BallX - i + 10 ) / 32 ] == 0 ) { BallX = BallX - i ; flag = 1 ; break ; } } /* if the ball does not touch a brick at the top, left or right */ if ( !flag ) { /* check if the ball has moved above the current layer */ if ( BallY < totallayer[layer - 1] ) { /* if so, change current layer appropriately */ layer-- ; max = totallayer[layer] ; } /* restore the image of the ball at the old coordinates */ putimage ( OldX, OldY, m1, OR_PUT ) ; /* erase the image at the old coordinates */ putimage ( OldX, OldY, m1, XOR_PUT ) ; /* place the image of the ball at the new coordinates */ putimage ( BallX, BallY, m1, XOR_PUT ) ; /* delay for fewseconds*/ delay ( speed ) ; /* carry on moving the ball */ continue ; } } /* when ball touch the brick control comes to this point */ bell ( 5 ) ; /* play music */ /* erase the touched brick */ delbrick ( ( BallX + 10 ) / 32, layer ) ; /* if the brick hit is on the extreme right */ if ( ( BallX + 10 ) / 32 == 19 ) line ( MaxX, 0, MaxX, 50 ) ; /* redraw right boundary */ /* if the brick hit is on the extreme left */ if ( ( BallX + 10 ) / 32 == 0 ) line ( 0, 0, 0, 50 ) ; /* redraw left boundary */ /* if the brick hit is in the topmost layer */ if ( layer == 0 ) line ( 0, 0, MaxX, 0 ) ; /* redraw top boundary */ /* set appropriate array element to 1 to indicate absence of brick */ bri[layer][ ( BallX + 10 ) / 32 ] = 1 ; BallY = BallY + 1 ; /* update the y coordinate */ dy = -dy ; /* change the current direction of the ball */ score += 10 ; /* increment the score by 10 */ gotoxy ( 16, 25 ) ; cout<< score; /* display latest score */ /* if the first brick is hit during a throw*/ } /* if ball reached the bottom */ if ( BallY > 180 - 12 ) { /* if paddle missed the ball */ if ( BallX < Base1 - 20 || BallX > Base1 + 50 ) { /* continue the decrement of the ball */ while ( BallY < 177 ) { /* erase the image of the ball at the old coordinates */ putimage ( OldX, OldY, m1, XOR_PUT ) ; /* put the image of the ball at the new coordinates */ putimage ( BallX, BallY, m1, XOR_PUT ) ; /* introduce delay for fewseconds */ delay ( speed ) ; /* saveing current x and y coordinates of the ball */ OldX = BallX ; OldY = BallY ; /* update ballx and bally to move the ball in correct direction */ BallX = BallX + dx ; BallY = BallY + dy ; } chance-- ; /* decrement the total number of chances */ score -= 10 ; /* decrement 10 points for each ball lost */ gotoxy ( 16, 25 ) ; cout<< score; /* display latest score */ bell ( 1 ) ; /* erase one of the available balls */ if ( chance ) putimage ( 515 + ( chance - 1 ) * 35 - 12 , MaxY - 10, m1, XOR_PUT ) ; /* if the last ball is being played */ if ( chance == 1 ) { gotoxy ( 45, 25 ) ; cout<< "Last ball... careful!"; } /* if all the balls are lost */ if ( !chance ) { gotoxy ( 45, 25 ) ; cout<<"Press any key to continue ... " ; outtextxy ( MidX, MidY, "Better luck next time" ) ; bell ( 2 ) ; closegraph() ; restorecrtmode() ; closegraph(); /* Close the graphics mode */ Initialize(); /* Intialize the graphics mode */ setbkcolor(4); SayGoodbye(); /* Display the That's all Folks message */ closegraph(); /* Return the system to text mode */ exit ( 0 ) ; } } /* if ball is collected on paddle */ bell ( 4 ) ; BallY = 180 - 12 ; /* restore the y coordinate of ball */ dy = -dy ; /* move the ball upwards */ } /* put the image of the ball at the old coordinates */ putimage ( OldX, OldY, m1, OR_PUT ) ; /* erase the image of the ball at the old coordinates */ putimage ( OldX, OldY, m1, XOR_PUT ) ; /* put the image of the ball at the upadted coordinates */ putimage ( BallX, BallY, m1, XOR_PUT ) ; /* if all the bricks have been knockout */ if ( score == 500 - ( ( 4 - chance ) * 20 ) ) { outtextxy ( MidX, MidY, "Winner !!" ) ; if ( score < 600 ) outtextxy ( MidX, MidY + 30, "Try to score 600" ) ; else outtextxy ( MidX, MidY + 30, " GREAT!" ) ; bell ( 2 ) ; closegraph() ; restorecrtmode() ; exit ( 0 ) ; } /* introduce delay for few seconds */ delay ( speed ) ; /* if the key is pressed to move the paddle */ if ( kbhit() ) { /* interrupt issue to obtain the ascii and scan codes of key hit */ ii.h.ah = 0 ; int86 ( 22, &ii, &oo ) ; /* put the image of the paddle at the old coordinates */ putimage ( Base1, Base2, m2, OR_PUT ) ; /* erase the image of the paddle at the old coordinates */ putimage ( Base1, Base2, m2, XOR_PUT ) ; /* if Esc key has been pressed */ if ( oo.h.ah == 1 ) exit ( 0 ) ; /* right arrow key */ if ( oo.h.ah == 75 ) Base1 = Base1 - 25 ; /* left arrow key */ if ( oo.h.ah == 77 ) Base1= Base1 + 25 ; /* if paddle goes beyond left boundary */ if ( Base1 < 0 ) Base1 = 0 ; /* if paddle goes beyond right boundary */ if ( Base1 > 589 ) Base1 = 589 ; /* put the image of the paddle at the proper position */ putimage ( Base1, Base2, m2, XOR_PUT ) ; } } closegraph(); Initialize(); SayGoodbye(); /* Give user the closing screen */ closegraph(); /* Return the system to text mode */ return(0); } /* This function creates the opening screen and displyed instruction related to the game */ screen() { int i, j, lx = 0, ly = 0, ch ; rectangle(1,1,600,195); setbkcolor(4); /* set the textstyle for displaying instruction */ changetextstyle ( DEFAULT_FONT, HORIZ_DIR, 0 ) ; outtextxy ( 150, 55, " Instructions " ) ; changetextstyle (4, HORIZ_DIR, 5 ); outtextxy ( 130, 0, " B R I C K S" ) ; changetextstyle ( DEFAULT_FONT, HORIZ_DIR, 0 ) ; outtextxy ( 30, 68, "Use left and right arrow keys to move paddle." ) ; outtextxy ( 30, 88, "If you don't collect the ball on the paddle, you lose the ball." ) ; outtextxy ( 30, 108, "On loosing a ball you loose 20 points." ) ; outtextxy ( 30, 128, "On taking a brick you gain 5 points." ) ; changetextstyle(7, HORIZ_DIR, 3); outtextxy ( 100, 148, "Press any key to continue ..." ) ; bell ( 3 ) ; /* ring music */ fflush ( stdin ) ; if ( getch() == 0 ) getch() ; closegraph(); initgraph ( &graphdriver, &graphmode, "c:\tc\bgi " ) ; rectangle(2,2,620,195); setbkcolor(4); /* display the main menu */ while ( 1 ) { changetextstyle(4,HORIZ_DIR,5); outtextxy ( 60, 8, "Options Available:" ) ; outtextxy ( 150, 55, "Play ( P )" ) ; outtextxy ( 150, 125, "Exit ( E )" ) ; ch = 0 ; /* continue untill you select the correct choice */ while ( ! ( ch == 'E' || ch == 'P' ) ) { fflush ( stdin ) ; /* if a special key is hit, flush the keyboard buffer */ if ( ( ch = getch() ) == 0 ) getch() ; else ch = toupper ( ch ) ; /* store the uppercase of the choice made*/ } if ( ch == 'P' ) break ; if (ch == 'E') exit ( 0 ) ; } setviewport ( 1, 125 - 12, MaxX - 1, MaxY - 1, 1 ) ; clearviewport() ; closegraph(); initgraph ( &graphdriver, &graphmode, "c:\tc\bgi " ) ; rectangle(2,2,620,195); setbkcolor(4); /* display menu for the diffrent levels */ changetextstyle(7,HORIZ_DIR,3); outtextxy ( 60, 8, "Select the level for play:" ) ; outtextxy ( 150,50, "Slow ( S )" ) ; outtextxy ( 150, 100, "Medium ( M )" ) ; outtextxy ( 150, 150, "Fast ( F )" ) ; /* accept user's choice */ fflush ( stdin ) ; if ( ( ch = getch() ) == 0 ) getch() ; clearviewport() ; /* return the choice selected by the user */ return ( ch ) ; } /* This function draws bricks at the start of the game.There are four layers of the bricks */ bricks() { int i, j, lx = 0, ly = 0 ; for ( i = 0 ; i < 5 ; i++ ) /* 5 rows */ { for ( j = 0 ; j < 30 ; j++ ) /* 20 columns */ { /* draw a brick at appropriate coordinates */ rectangle ( lx, ly, lx + 20, ly + 7 ) ; floodfill ( lx + 1, ly + 1, 2 ) ; lx = lx + 32 ; } lx = 0 ; ly = ly + 10 ; } } /* This function erases the brick which is knock by the ball */ delbrick ( int b, int l ) { /* b - brick number, l - layer */ setcolor ( BLACK ) ; rectangle ( b * 32, l * 10, ( b * 32 ) + 20 , ( l * 10 ) + 7 ) ; rectangle ( b * 32 + 1, l * 10, ( b * 32 ) + 20 - 1, ( l * 10 ) + 7 - 1 ) ; rectangle ( b * 32 + 2, l * 10, ( b * 32 ) + 20 - 2, ( l * 10 ) + 7 - 2 ) ; rectangle ( b * 32 + 3, l * 10, ( b * 32 ) + 20 - 3, ( l * 10 ) + 7 - 3 ) ; rectangle ( b * 32 + 4, l * 10, ( b * 32 ) + 20 - 4, ( l * 10 ) + 7 - 4 ) ; rectangle ( b * 32 + 5, l * 10, ( b * 32 ) + 20 - 5, ( l * 10 ) + 7 - 5 ) ; rectangle ( b * 32 + 6, l * 10, ( b * 32 ) + 20 - 6, ( l * 10 ) + 7 - 6 ) ; setcolor ( CGA_YELLOW ) ; } /* plays different types of music */ bell ( int m_no ) { /* natural frequencies of 7 notes */ float wave[6] = { 120.81, 136.83, 144.81, 154.61, 216, 240 } ; int n, i ; switch ( m_no ) { case 1 : for ( i = 0 ; i < 6 ; i++ ) { sound ( wave[i] * 1 ) ; delay ( 30 ) ; } nosound() ; break ; case 2 : for ( i = 0 ; i < 15 ; i++ ) { n = random ( 6 ) ; sound ( wave[n] * 2 ) ; delay ( 100 ) ; } nosound() ; break ; case 3 : while ( !kbhit() ) { n = random ( 6 ) ; sound ( wave[n] * 2 ) ; delay ( 100 ) ; } nosound() ; /* flush the keyboard buffer */ if ( getch() == 0 ) getch() ; break ; case 4 : for ( i = 5 ; i >= 0 ; i-- ) { sound ( wave[i] * 4 ) ; delay ( 15 ) ; } nosound() ; break ; case 5 : sound ( wave[2] * 5 ) ; delay ( 50 ) ; nosound() ; } } /* */ /* INITIALIZE: Initializes the graphics system and reports */ /* any errors which occured. */ /* */ void Initialize(void) { int xasp, yasp; /* Used to read the aspect ratio*/ GraphDriver = DETECT; /* Request auto-detection */ initgraph( &GraphDriver, &GraphMode, "c:\tc\bgi" ); ErrorCode = graphresult(); /* Read result of initialization*/ if( ErrorCode != grOk ){ /* Error occured during init */ printf(" Graphics System Error: %s ", grapherrormsg( ErrorCode ) ); exit( 1 ); } getpalette( &palette ); /* Read the palette from board */ MaxColors = getmaxcolor() + 1; /* Read maximum number of colors*/ MaxXX = getmaxx(); MaxYY = getmaxy(); /* Read size of screen */ getaspectratio( &xasp, &yasp ); /* read the hardware aspect */ AspectRatio = (double)xasp / (double)yasp; /* Get correction factor */ } /* */ /* SAYGOODBYE: Give a closing screen to the user before leaving. */ /* */ void SayGoodbye(void) { struct viewporttype viewinfo; /* Structure to read viewport */ int h, w; MainWindow( "== Finale ==" ); getviewsettings( &viewinfo ); /* Read viewport settings */ changetextstyle( TRIPLEX_FONT, HORIZ_DIR, 4 ); settextjustify( CENTER_TEXT, CENTER_TEXT ); h = viewinfo.bottom - viewinfo.top; w = viewinfo.right - viewinfo.left; outtextxy( w/2, h/2, "That's all, folks!" ); StatusLine( "Press any key to EXIT" ); getch(); cleardevice(); /* Clear the graphics screen */ } /* */ /* MAINWINDOW: Establish the main window for the demo and set */ /* a viewport for the demo code. */ /* */ void MainWindow( char *header ) { int height; cleardevice(); /* Clear graphics screen */ setcolor( MaxColors - 1 ); /* Set current color to white */ setviewport( 0, 0, MaxXX, MaxYY, 1 ); /* Open port to full screen */ height = textheight( "H" ); /* Get basic text height */ changetextstyle( DEFAULT_FONT, HORIZ_DIR, 1 ); settextjustify( CENTER_TEXT, TOP_TEXT ); outtextxy( MaxXX/2, 2, header ); setviewport( 0, height+4, MaxXX, MaxYY-(height+4), 1 ); DrawBorder(); setviewport( 1, height+5, MaxXX-1, MaxYY-(height+5), 1 ); } /* */ /* STATUSLINE: Display a status line at the bottom of the screen. */ /* */ void StatusLine( char *msg ) { int height; setviewport( 0, 0, MaxXX, MaxYY, 1 ); /* Open port to full screen */ setcolor( MaxColors - 1 ); /* Set current color to white */ changetextstyle( DEFAULT_FONT, HORIZ_DIR, 1 ); settextjustify( CENTER_TEXT, TOP_TEXT ); setlinestyle( SOLID_LINE, 0, NORM_WIDTH ); setfillstyle( EMPTY_FILL, 0 ); height = textheight( "H" ); /* Detemine current height */ bar( 0, MaxYY-(height+4), MaxXX, MaxYY ); rectangle( 0, MaxYY-(height+4), MaxXX, MaxYY ); outtextxy( MaxXX/2, MaxYY-(height+2), msg ); setviewport( 1, height+5, MaxXX-1, MaxYY-(height+5), 1 ); } /* */ /* DRAWBORDER: Draw a solid single line around the current */ /* viewport. */ /* */ void DrawBorder(void) { struct viewporttype vp; setcolor( MaxColors - 1 ); /* Set current color to white */ setlinestyle( SOLID_LINE, 0, NORM_WIDTH ); getviewsettings( &vp ); rectangle( 0, 0, vp.right-vp.left, vp.bottom-vp.top ); } /* */ /* CHANGETEXTSTYLE: similar to settextstyle, but checks for */ /* errors that might occur whil loading the font file. */ /* */ void changetextstyle(int font, int direction, int charsize) { int ErrorCode; graphresult(); /* clear error code */ settextstyle(font, direction, charsize); ErrorCode = graphresult(); /* check result */ if( ErrorCode != grOk ){ /* if error occured */ closegraph(); printf(" Graphics System Error: %s ", grapherrormsg( ErrorCode ) ); exit( 1 ); } } /* The main function body of main screen which displays the main screen creating the opening screen display */ mainscreen() { int maxx, maxy, in, area; // get maximum x, y coordinates of the screen maxx = getmaxx(); maxy = getmaxy(); // setbkcolor sets the current background color using the palette setbkcolor(RED); // Draws a rectangle (graphics mode) rectangle(0, 0, maxx, maxy); // sets the line style and text justification in screen changetextstyle(1, HORIZ_DIR, 0); // displaying the output text on main screen outtextxy(220, 20, "WELCOME"); outtextxy(240,60," TO "); outtextxy(220,100," BRICKS"); changetextstyle(7, HORIZ_DIR, 3); bell(3); outtextxy(110, 150, "Press any key to continue..."); // Flushes the standard input device fflush(stdin); getch(); closegraph(); }

/* display the text or string at a specified point (x, y) on the screen by outtextxy() function example */ // C Implementation for outtextxy() #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // outtextxy function outtextxy(200, 150, "Hello, Have a good day !"); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* deallocate all memory allocated by the graphics system by closegraph() function example */ // C Implementation for closegraph() #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // outtext function displays // text at current position. outtext("Press any key to close" " the graphics mode !!"); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* write a C program which demonstrate use of if-else-if ladder statement */ #include<stdio.h> #include<conio.h> void main() { int a; printf("Enter a Number: "); scanf("%d",&a); if(a > 0) { printf("Given Number is Positive"); } else if(a == 0) { printf("Given Number is Zero"); } else if(a < 0) { printf("Given Number is Negative"); } getch(); }

/* establishes a new viewport for graphics output by setviewport() function code example */ #include <graphics.h> #include <conio.h> int main() { //initilizing graphic driver and //graphic mode variable int graphicdriver=DETECT,graphicmode; //calling initgraph with parameters initgraph(&graphicdriver,&graphicmode,"c:\\turboc3\\bgi"); //Printing message for user outtextxy(50, 50 + 50, "Program to try setviewport in C graphics"); //declaring variable; int middleofx, middleofy; //getting middle of x and y middleofx = getmaxx()/2; middleofy = getmaxy()/2; //setting viewport setviewport(middleofx - 50, middleofy - 50, middleofx + 50, middleofy + 50, 1); //creating circle circle(50, 50, 55); getch(); return 0; }

/* #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. */ #include <stdio.h> #include <string.h> typedef struct Books { char title[50]; char author[50]; char subject[100]; int book_id; } Book; int main( ) { Book book; strcpy( book.title, "C Programming"); strcpy( book.author, "XCoder"); strcpy( book.subject, "C Programming Tutorial"); book.book_id = 6495407; printf( "Book title : %s\n", book.title); printf( "Book author : %s\n", book.author); printf( "Book subject : %s\n", book.subject); printf( "Book book_id : %d\n", book.book_id); return 0; }

/* The continue statement skips the current iteration of the loop and continues with the next iteration. */ // Program to calculate the sum of numbers (10 numbers max) // If the user enters a negative number, it's not added to the result #include <stdio.h> int main() { int i; double number, sum = 0.0; for (i = 1; i <= 10; ++i) { printf("Enter a n%d: ", i); scanf("%lf", &number); if (number < 0.0) { continue; } sum += number; // sum = sum + number; } printf("Sum = %.2lf", sum); return 0; }

/* bring the program control out of the loop by break keyword */ // Program to calculate the sum of numbers (10 numbers max) // If the user enters a negative number, the loop terminates #include <stdio.h> int main() { int i; double number, sum = 0.0; for (i = 1; i <= 10; ++i) { printf("Enter n%d: ", i); scanf("%lf", &number); // if the user enters a negative number, break the loop if (number < 0.0) { break; } sum += number; // sum = sum + number; } printf("Sum = %.2lf", sum); return 0; }

/* #include directive tells the preprocessor to insert the contents of another file into the source code at the point where the #include directive is found. */ // C program to illustrate file inclusion // <> used to import system header file #include <stdio.h> // " " used to import user-defined file #include "process.h" // main function int main() { // add function defined in process.h add(10, 20); // mult function defined in process.h multiply(10, 20); // printf defined in stdio.h printf("Process completed"); return 0; }

/* draw a rectangle by rectangle() function example */ // C program to draw a rectangle #include <graphics.h> // Driver code int main() { // gm is Graphics mode which is a computer display // mode that generates image using pixels. // DETECT is a macro defined in "graphics.h" header file int gd = DETECT, gm; // location of left, top, right, bottom int left = 150, top = 150; int right = 450, bottom = 450; // initgraph initializes the graphics system // by loading a graphics driver from disk initgraph(&gd, &gm, ""); // rectangle function rectangle(left, top, right, bottom); getch(); // closegraph function closes the graphics // mode and deallocates all memory allocated // by graphics system . closegraph(); return 0; }

/* logical operators in C language */ #include <stdio.h> main() { int a = 4; int b = 23; int c ; if ( a && b ) { printf("Line 1 - Condition is true\n" ); } if ( a || b ) { printf("Line 2 - Condition is true\n" ); } /* lets change the value of a and b */ a = 2; b = 8; if ( a && b ) { printf("Line 3 - Condition is true\n" ); } else { printf("Line 3 - Condition is not true\n" ); } if ( !(a && b) ) { printf("Line 4 - Condition is true\n" ); } }

/* place cursor at a desired location on screen by gotoxy() function example */ #include <stdio.h> //to use 'gotoxy()' and 'getch()' #include <conio.h> int main() { // define the type of variables int a, b; // define the value of variables a = 50; b = 30; // change cursor position on further co-ordinates. gotoxy(a, b); // message printf("The position of cursor is changed"); // for killing the execution getch(); return 0; }

/* check whether a key is pressed or not by kbhit() function example */ #include <stdio.h> #include <conio.h> main() { char ch; printf("Enter keys (ESC to exit)\n"); while (1) { //define infinite loop for taking keys if (kbhit) { ch = getch(); // Get typed character into ch if ((int)ch == 27) //when esc button is pressed, then it will comeout from loop break; printf("You have entered : %c\n", ch); } } }

/* get the maximum Y coordinate for current graphics mode and driver by getmaxy() function code example */ #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // sprintf stands for "String print". // Instead of printing on console, it // store output on char buffer which // are specified in sprintf sprintf(arr, "Maximum Y coordinate for current " "graphics mode And driver = %d", getmaxy()); // outtext function displays text at // current position. outtext(arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* for loop statement in C language */ // Program to calculate the sum of first n natural numbers // Positive integers 1,2,3...n are known as natural numbers #include <stdio.h> int main() { int num, count, sum = 0; printf("Enter a positive integer: "); scanf("%d", &num); // for loop terminates when num is less than count for(count = 1; count <= num; ++count) { sum += count; } printf("Sum = %d", sum); return 0; }

/* determine the size of memory required to store an image by imagesize() function code example */ #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm, color, bytes; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // Draws a circle with center at // (200, 200) and radius as 50. circle(200, 200, 50); // draws a line with 2 points line(150, 200, 250, 200); // draws a line with 2 points line(200, 150, 200, 250); // imagesize function bytes = imagesize(150, 150, 250, 250); // sprintf stands for "String print". // Instead of printing on console, // it store output on char buffer // which are specified in sprintf sprintf(arr, "Number of bytes required " "to store required area = %d", bytes); // outtext function displays text // at current position. outtextxy(20, 280, arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* compute the height of strings by textheight() function code example */ #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm, color, height; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // textheight function height = textheight("I love Clementine"); //sprintf stands for "String print". //Instead of printing on console, //it store output on char buffer //which are specified in sprintf sprintf(arr, "Textheight is = %d", height); //outtext function displays text //at current position. outtext(arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* justify text output around the current position (CP) horizontally and vertically, as specified by settextjustify() function example */ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> /* function prototype */ void xat(int x, int y); /* horizontal text justification settings */ char *hjust[] = { "LEFT_TEXT", "CENTER_TEXT", "RIGHT_TEXT" }; /* vertical text justification settings */ char *vjust[] = { "BOTTOM_TEXT", "CENTER_TEXT", "TOP_TEXT" }; int main(void) { /* request autodetection */ int gdriver = DETECT, gmode, errorcode; int midx, midy, hj, vj; char msg[80]; /* initialize graphics and local variables */ initgraph(&gdriver, &gmode, ""); /* read result of initialization */ errorcode = graphresult(); if (errorcode != grOk) { /* an error occurred */ printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); /* terminate with an error code */ } midx = getmaxx() / 2; midy = getmaxy() / 2; /* loop through text justifications */ for (hj=LEFT_TEXT; hj<=RIGHT_TEXT; hj++) for (vj=LEFT_TEXT; vj<=RIGHT_TEXT; vj++) { cleardevice(); /* set the text justification */ settextjustify(hj, vj); /* create a message string */ sprintf(msg, "%s %s", hjust[hj], vjust[vj]); /* create crosshairs on the screen */ xat(midx, midy); /* output the message */ outtextxy(midx, midy, msg); getch(); } /* clean up */ closegraph(); return 0; } void xat(int x, int y) /* draw an x at (x,y) */ { line(x-4, y, x+4, y); line(x, y-4, x, y+4); }

/* wait for any character input from keyboard by getch() function example. */ // C code to illustrate working of // getch() to accept hidden inputs #include <conio.h> #include <dos.h> // delay() #include <stdio.h> #include <string.h> void main() { // Taking the password of 8 characters char pwd[9]; int i; // To clear the screen clrscr(); printf("Enter Password: "); for (i = 0; i < 8; i++) { // Get the hidden input // using getch() method pwd[i] = getch(); // Print * to show that // a character is entered printf("*"); } pwd[i] = '\0'; printf("\n"); // Now the hidden input is stored in pwd[] // So any operation can be done on it // Here we are just printing printf("Entered password: "); for (i = 0; pwd[i] != '\0'; i++) printf("%c", pwd[i]); // Now the console will wait // for a key to be pressed getch(); }

/* print formatted data to stdout by printf() function example */ #include <stdio.h> int main() { char ch; char str[100]; int a; float b; printf("Enter any character \n"); scanf("%c", &ch); printf("Entered character is %c \n", ch); printf("Enter any string ( upto 100 character ) \n"); scanf("%s", &str); printf("Entered string is %s \n", str); printf("Enter integer and then a float: "); // Taking multiple inputs scanf("%d%f", &a, &b); printf("You entered %d and %f", a, b); return 0; }

/* set the current drawing color to color, which can range from 0 to getmaxcolor by setcolor() function example */ // C Implementation for setcolor() #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm, color; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // Draws circle in white color // center at (100, 100) and radius // as 50 circle(100, 100, 50); // setcolor function setcolor(GREEN); // Draws circle in green color // center at (200, 200) and radius // as 50 circle(200, 200, 50); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* get the maximum X coordinate for current graphics mode and driver by getmaxx() function code example */ #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // sprintf stands for "String print". // Instead of printing on console, it // store output on char buffer which // are specified in sprintf sprintf(arr, "Maximum X coordinate for current " "graphics mode And driver = %d", getmaxx()); // outtext function displays text at // current position. outtext(arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* suspend execution of a program for a particular time by delay() function example */ #include <stdio.h> //to use 'delay()' #include <dos.h> int main() { // message for user printf("After printing this message the program will get end in next 5 seconds \n"); // delay the process for 5 seconds as it takes integer value in milliseconds. delay(5000); // message for user. printf("After printing this message the program will get delay for next 15 seconds\n"); // to terminate the process for next 15 seconds. sleep(15); // message for user printf("After printing this message the program will get end in next 2 seconds \n"); // delay the process for 2 seconds as it takes integer value in milliseconds. delay(2000); return 0; }

/* produce the sound of a specified frequency by sound() function example */ #include <stdio.h> //to use 'sound()', 'delay()' functions #include <dos.h> int main() { //calling the function for producing //the sound of frequency 400. sound(400); //function to delay the sound for //half of second. delay(500); //the sound of frequency 200. sound(200); //the sound of frequency 500. sound(500); //calling the function to stop the //system sound. nosound(); return 0; }

/* if else statement in C language */ // Check whether an integer is odd or even #include <stdio.h> int main() { int number; printf("Enter an integer: "); scanf("%d", &number); // True if the remainder is 0 if (number%2 == 0) { printf("%d is an even integer.",number); } else { printf("%d is an odd integer.",number); } return 0; }

/* fill an enclosed area on bitmap devices by floodfill() function code example */ #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading // a graphics driver from disk initgraph(&gd, &gm, " "); // center and radius of circle int x_circle = 250; int y_circle = 250; int radius=100; // setting border color int border_color = WHITE; // set color and pattern setfillstyle(HATCH_FILL,RED); // x and y is a position and // radius is for radius of circle circle(x_circle,y_circle,radius); // fill the color at location // (x, y) with in border color floodfill(x_circle,y_circle,border_color); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system closegraph(); return 0; }

/* clear the screen in graphics mode and set the current position to (0,0) by cleardevice() function example.*/ #include <graphics.h> #include <conio.h> int main() { //initilizing graphic driver and //graphic mode variable int graphicdriver=DETECT,graphicmode; //calling initgraph initgraph(&graphicdriver,&graphicmode,"c:\\turboc3\\bgi"); //Printing message for user outtextxy(20, 20 + 20, "Program to use graph default in C graphics"); //message to clear screen outtextxy(20, 50 + 30, "Press any key to clear screen"); //getting character and clear the device screen getch(); cleardevice(); //message to press key to get exit from program outtextxy(20, 20 + 20, "Press any key to exit..."); getch(); return 0; }

/* restore the original video mode detected by initgraph by restorecrtmode() function example. */ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> int main(void) { /* request auto detection */ int gd = DETECT, gmode, err; int midx, midy; /* initialize graphics and local variables */ initgraph(&gd, &gmode, "C:/TURBOC3/BGI"); /* read result of initialization */ err = graphresult(); if (err != grOk) { /* an error occurred */ printf("Graphics error: %s\n", grapherrormsg(err)); getch(); return 0; } /* mid position in x and y-axis */ midx = getmaxx() / 2; midy = getmaxy() / 2; /* output a message */ settextjustify(CENTER_TEXT, CENTER_TEXT); outtextxy(midx, midy - 100, "GRAPHICS MODE"); /* draw a rectange at the given position */ rectangle(midx - 50, midy - 50, midx + 50, midy + 50); getch(); /* restore system to text mode */ restorecrtmode(); printf("Restored system to text mode"); getch(); /* return to graphics mode */ setgraphmode(getgraphmode()); /* output a message */ settextjustify(CENTER_TEXT, CENTER_TEXT); outtextxy(midx, midy - 100, "BACK TO GRAPHIC MODE!!"); /* draws a rectangle at the given postion */ rectangle(midx - 50, midy - 50, midx + 50, midy + 50); /* clean up */ getch(); closegraph(); return 0; }

/* allocate memory block by malloc() function example */ // Program to calculate the sum of n numbers entered by the user #include <stdio.h> #include <stdlib.h> int main() { int n, i, *ptr, sum = 0; printf("Enter number of elements: "); scanf("%d", &n); ptr = (int*) malloc(n * sizeof(int)); // if memory cannot be allocated if(ptr == NULL) { printf("Error! memory not allocated."); exit(0); } printf("Enter elements: "); for(i = 0; i < n; ++i) { scanf("%d", ptr + i); sum += *(ptr + i); } printf("Sum = %d", sum); // deallocating the memory free(ptr); return 0; }

/* initgraph initializes the graphics system by loading a graphics driver by initgraph() function example*/ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> int main(void) { /* request auto detection */ int gdriver = DETECT, gmode, errorcode; /* initialize graphics mode */ initgraph(&gdriver, &gmode, ""); /* read result of initialization */ errorcode = graphresult(); if (errorcode != grOk) /* an error occurred */ { printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); /* return with error code */ } /* draw a line */ line(0, 0, getmaxx(), getmaxy()); /* clean up */ getch(); closegraph(); return 0; }

/* clean (or flush) the output buffer and transfer the buffered data into the terminal (in the case of stdout) or disk (throughout the case of file output) by fflush() function example. */ #include <stdio.h> #include <string.h> int main () { char buff[1024]; memset( buff, '\0', sizeof( buff )); fprintf(stdout, "Going to set full buffering on\n"); setvbuf(stdout, buff, _IOFBF, 1024); fprintf(stdout, "HappyCodings.com\n"); fprintf(stdout, "This output will go into buff\n"); fflush( stdout ); fprintf(stdout, "and this will appear when programm\n"); fprintf(stdout, "will come after sleeping 5 seconds\n"); sleep(5); return(0); }

/* call all functions registered with atexit and terminates the program by exit() function example */ #include <stdio.h> #include <stdlib.h> int main () { // declaration of the variables int i, num; printf ( " Enter the last number: "); scanf ( " %d", &num); for ( i = 1; i<num; i++) { // use if statement to check the condition if ( i == 6 ) /* use exit () statement with passing 0 argument to show termination of the program without any error message. */ exit(0); else printf (" \n Number is %d", i); } return 0; }

/* write string to stdout by puts() function example */ #include <stdio.h> #include <string.h> int main() { char name[50]; printf("Enter your name "); gets(name); int age[50]; printf("Enter your age "); gets(age); char address[50]; printf("Enter your address "); gets(address); int pincode[50]; printf("Enter your pincode "); gets(pincode); printf("Entered Name is: "); puts(name); printf("Entered age is: "); puts(age); printf("Entered address is: "); puts(address); printf("Entered pincode is: "); puts(pincode); getch(); return 0; }

/* while loop statement in C language */ #include<stdio.h> int main() { int n, num, sum = 0, remainder; printf("Enter a number: "); scanf("%d", &n); num = n; // keep looping while n > 0 while( n > 0 ) { remainder = n % 10; // get the last digit of n sum += remainder; // add the remainder to the sum n /= 10; // remove the last digit from n } printf("Sum of digits of %d is %d", num, sum); // signal to operating system everything works fine return 0; }

/* unions in C language */ #include <stdio.h> #include <string.h> union student { char name[20]; char subject[20]; float percentage; }; int main() { union student record1; union student record2; // assigning values to record1 union variable strcpy(record1.name, "Jack"); strcpy(record1.subject, "Red"); record1.percentage = 96.23; printf("Union record1 values example\n"); printf(" Name : %s \n", record1.name); printf(" Subject : %s \n", record1.subject); printf(" Percentage : %f \n\n", record1.percentage); // assigning values to record2 union variable printf("Union record2 values example\n"); strcpy(record2.name, "Mani"); printf(" Name : %s \n", record2.name); strcpy(record2.subject, "Physics"); printf(" Subject : %s \n", record2.subject); record2.percentage = 99.50; printf(" Percentage : %f \n", record2.percentage); return 0; }

/* return the maximum color value by getmaxcolor() graphic function code example */ // C Implementation for getmaxcolor() #include <graphics.h> #include <stdio.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; char arr[100]; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // sprintf stands for "String print". // Instead of printing on console, it // store output on char buffer which // are specified in sprintf sprintf(arr, "Maximum number of colors for " "current graphics mode and " "driver = %d", getmaxcolor() + 1); // outtext function displays text // at current position. outtextxy(20, 100, arr); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* convert lowercase letter to uppercase by toupper() function example */ //Example for toupper in C Programming #include <stdio.h> #include <ctype.h> int main() { char ch; printf("Please Enter Any Valid Character: \n"); scanf("%c", &ch); if(isalpha(ch)) { printf("\n We Converted Your character to Upper Case = %c", toupper(ch)); } else { printf("\n Please Enter a Valid character"); } }

/* set the background to the color specified by color by setbkcolor() function example */ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> int main(void) { /* _select driver and mode that supports multiple background colors*/ int gdriver = EGA, gmode = EGAHI, errorcode; int bkcol, maxcolor, x, y; char msg[80]; /* initialize graphics and local variables */ initgraph(&gdriver, &gmode, ""); /* read result of initialization */ errorcode = graphresult(); if (errorcode != grOk) { /* an error occurred */ printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); /* terminate with an error code */ } /* maximum color index supported */ maxcolor = getmaxcolor(); /* for centering text messages */ settextjustify(CENTER_TEXT, CENTER_TEXT); x = getmaxx() / 2; y = getmaxy() / 2; /* loop through the available colors */ for (bkcol=0; bkcol<=maxcolor; bkcol++) { /* clear the screen */ cleardevice(); /* select a new background color */ setbkcolor(bkcol); /* output a messsage */ if (bkcol == WHITE) setcolor(EGA_BLUE); sprintf(msg, "Background color: %d", bkcol); outtextxy(x, y, msg); getch(); } /* clean up */ closegraph(); return 0; }

/* assignment operators in C language */ #include <stdio.h> main() { int a = 23; int c ; c = a; printf("Line 1 - = Operator Example, Value of c = %d\n", c ); c += a; printf("Line 2 - += Operator Example, Value of c = %d\n", c ); c -= a; printf("Line 3 - -= Operator Example, Value of c = %d\n", c ); c *= a; printf("Line 4 - *= Operator Example, Value of c = %d\n", c ); c /= a; printf("Line 5 - /= Operator Example, Value of c = %d\n", c ); c = 120; c %= a; printf("Line 6 - %= Operator Example, Value of c = %d\n", c ); c <<= 2; printf("Line 7 - <<= Operator Example, Value of c = %d\n", c ); c >>= 2; printf("Line 8 - >>= Operator Example, Value of c = %d\n", c ); c &= 2; printf("Line 9 - &= Operator Example, Value of c = %d\n", c ); c ^= 2; printf("Line 10 - ^= Operator Example, Value of c = %d\n", c ); c |= 2; printf("Line 11 - |= Operator Example, Value of c = %d\n", c ); }

/* draw a 2-dimensional, rectangular filled in bar by bar() function example */ // C implementation of bar() function #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // location of sides int left, top, right, bottom; // left, top, right, bottom denotes // location of rectangular bar bar(left = 150, top = 150, right = 190, bottom = 350); bar(left = 220, top = 250, right = 260, bottom = 350); bar(left = 290, top = 200, right = 330, bottom = 350); // y axis line line(100, 50, 100, 350); // x axis line line(100, 350, 400, 350); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* clear the current viewport by clearviewport() function code example */ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> #define CLIP_ON 1 /* activates clipping in viewport */ int main(void) { /* request autodetection */ int gdriver = DETECT, gmode, errorcode, ht; /* initialize graphics and local variables */ initgraph(&gdriver, &gmode, ""); /* read result of initialization */ errorcode = graphresult(); if (errorcode != grOk) { /* an error occurred */ printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); /* terminate with an error code */ } setcolor(getmaxcolor()); ht = textheight("W"); /* message in default full-screen viewport */ outtextxy(0, 0, "* <-- (0, 0) in default viewport"); /* create a smaller viewport */ setviewport(50, 50, getmaxx()-50, getmaxy()-50, CLIP_ON); /* display some messages */ outtextxy(0, 0, "* <-- (0, 0) in smaller viewport"); outtextxy(0, 2*ht, "Press any key to clear viewport:"); getch(); /* wait for a key */ clearviewport(); /* clear the viewport */ /* output another message */ outtextxy(0, 0, "Press any key to quit:"); /* clean up */ getch(); closegraph(); return 0; }

/* draw a line from a point(x1,y1) to point(x2,y2) by line() function example */ /*C graphics program to draw a line.*/ #include <graphics.h> #include <conio.h> main() { int gd = DETECT, gm; //init graphics initgraph(&gd, &gm, "C:/TURBOC3/BGI"); /* if you are using turboc2 use below line to init graphics: initgraph(&gd, &gm, "C:/TC/BGI"); */ //draw a line /* line() function description parameter left to right x1: 100 y1: 100 x2: 200 y2: 100 */ line(100,100,200,100); //will draw a horizontal line line(10,10,200,10); //will draw another horizonatl line getch(); closegraph(); return 0; }

/* set the text font, the direction in which text is displayed, and the size of the characters by settextstyle() function example. */ // C++ implementation for // settextstyle() function #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading // a graphics driver from disk initgraph(&gd, &gm, ""); // location of text int x = 150; int y = 150; // font style int font = 8; // font direction int direction = 0; // font size int font_size = 5; // for setting text style settextstyle(font, direction, font_size); // for printing text in graphics window outtextxy(x, y, "Happy Codings"); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by graphics // system . closegraph(); return 0; }

/* set the style for all lines drawn by line, lineto, rectangle, drawpoly by setlinestyle() function example */ // C Implementation for setlinestyle() #include <graphics.h> // driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // variable to change the // line styles int c; // initial coordinate to // draw line int x = 200, y = 100; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // To keep track of lines for ( c = 0 ; c < 5 ; c++ ) { // setlinestyle function setlinestyle(c, 0, 1); // Drawing line line(x, y, x+200, y); y = y + 25; } getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* put the bit image onto the screen by putimage() function code example */ #include<stdio.h> #include<conio.h> #include<graphics.h> void main() { int gd=DETECT, gm,size; char *buff; initgraph(&gd,&gm," "); outtextxy(100,80,"Original image:"); rectangle(100,200,200,275); size=http://www.website.com/imagesize(100,200,200,275); buf=malloc(size); getimage(100,200,200,275,buf); outtextxy(100,320,"Captured image:"); putimage(100,340,buf,COPY_PUT); getch(); closegraph(); }

/* draw a circle with center at (x, y) and given radius by circle() function example. */ // C Implementation for drawing circle #include <graphics.h> //driver code int main() { // gm is Graphics mode which is // a computer display mode that // generates image using pixels. // DETECT is a macro defined in // "graphics.h" header file int gd = DETECT, gm; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // circle function circle(250, 200, 50); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); return 0; }

/* transfer control of the program to the specified label by goto statement example */ // Program to calculate the sum and average of positive numbers // If the user enters a negative number, the sum and average are displayed. #include <stdio.h> int main() { const int maxInput = 100; int i; double number, average, sum = 0.0; for (i = 1; i <= maxInput; ++i) { printf("%d. Enter a number: ", i); scanf("%lf", &number); // go to jump if the user enters a negative number if (number < 0.0) { goto jump; } sum += number; } jump: average = sum / (i - 1); printf("Sum = %.2f\n", sum); printf("Average = %.2f", average); return 0; }

/* set the current fill pattern and fill color by setfillstyle() function example */ #include<stdio.h> #include<conio.h> #include<graphics.h> void main() { int gd=DETECT, gm,bkcolor; initgraph(&gd,&gm," "); setfillstyle(EMPTY_FILL,YELLOW); bar3d(2,150,100,200,25,1); setfillstyle(SOLID_FILL,RED); bar3d(150,150,250,200,25,1); setfillstyle(LINE_FILL,BLUE); bar3d(300,150,400,200,25,1); setfillstyle(LTSLASH_FILL,GREEN); bar3d(450,150,550,200,25,1); setfillstyle(SLASH_FILL,CYAN); bar3d(2,250,100,300,25,1); setfillstyle(BKSLASH_FILL,BROWN); bar3d(150,250,250,300,25,1); setfillstyle(LTBKSLASH_FILL,MAGENTA); bar3d(300,250,400,300,25,1); setfillstyle(HATCH_FILL,LIGHTRED); bar3d(450,250,550,300,25,1); setfillstyle(XHATCH_FILL,DARKGRAY); bar3d(2,350,100,400,25,1); setfillstyle(INTERLEAVE_FILL,YELLOW); bar3d(150,350,250,400,25,1); setfillstyle(WIDE_DOT_FILL,LIGHTMAGENTA); bar3d(300,350,400,400,25,1); setfillstyle(CLOSE_DOT_FILL,LIGHTGRAY); bar3d(450,350,550,400,25,1); getch(); closegraph(); }

/* copy an image from the screen to memory by getimage() function code example */ #include <graphics.h> #include <stdlib.h> #include <stdio.h> #include <conio.h> #include <alloc.h> void save_screen(void *buf[4]); void restore_screen(void *buf[4]); int maxx, maxy; int main(void) { int gdriver=DETECT, gmode, errorcode; void *ptr[4]; /* autodetect the graphics driver and mode */ initgraph(&gdriver, &gmode, ""); errorcode = graphresult(); /* check for any errors */ if (errorcode != grOk) { printf("Graphics error: %s\n", grapherrormsg(errorcode)); printf("Press any key to halt:"); getch(); exit(1); } maxx = getmaxx(); maxy = getmaxy(); /* draw an image on the screen */ rectangle(0, 0, maxx, maxy); line(0, 0, maxx, maxy); line(0, maxy, maxx, 0); save_screen(ptr); /* save the current screen */ getch(); /* pause screen */ cleardevice(); /* clear screen */ restore_screen(ptr); /* restore the screen */ getch(); /* pause screen */ closegraph(); return 0; } void save_screen(void *buf[4]) { unsigned size; int ystart=0, yend, yincr, block; yincr = (maxy+1) / 4; yend = yincr; /* get byte size of image */ size = imagesize(0, ystart, maxx, yend); for (block=0; block<=3; block++) { if ((buf[block] = farmalloc(size)) == NULL) { closegraph(); printf("Error: not enough heap space in save_screen().\n"); exit(1); } getimage(0, ystart, maxx, yend, buf[block]); ystart = yend + 1; yend += yincr + 1; } } void restore_screen(void *buf[4]) { int ystart=0, yend, yincr, block; yincr = (maxy+1) / 4; yend = yincr; for (block=0; block<=3; block++) { putimage(0, ystart, buf[block], COPY_PUT); farfree(buf[block]); ystart = yend + 1; yend += yincr + 1; } }

/* silent the system by nosound() function example */ #include <stdio.h> //to use 'sound()', 'delay()' functions #include <dos.h> int main() { //calling the function for producing //the sound of frequency 400. sound(400); //function to delay the sound for //half of second. delay(500); //calling the function for producing //the sound of frequency 250. sound(250); //function to delay the sound for //half of second. delay(500); //calling the function to stop the //system sound. nosound(); return 0; }

/* switch case statement in C language*/ // Program to create a simple calculator #include <stdio.h> int main() { char operation; double n1, n2; printf("Enter an operator (+, -, *, /): "); scanf("%c", &operation); printf("Enter two operands: "); scanf("%lf %lf",&n1, &n2); switch(operation) { case '+': printf("%.1lf + %.1lf = %.1lf",n1, n2, n1+n2); break; case '-': printf("%.1lf - %.1lf = %.1lf",n1, n2, n1-n2); break; case '*': printf("%.1lf * %.1lf = %.1lf",n1, n2, n1*n2); break; case '/': printf("%.1lf / %.1lf = %.1lf",n1, n2, n1/n2); break; // operator doesn't match any case constant +, -, *, / default: printf("Error! operator is not correct"); } return 0; }