C Programming Code Examples

/* Prog to implement a boolean function using a multiplexer logic */ #include<dos.h> #include<math.h> #include<stdio.h> #include<conio.h> #include<stdlib.h> #include<graphics.h> #define N 500 int function[35]; int strobe[5] = { 0,0,0,0,0 }; int store[16] = { 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2 }; int inputs[16]; int output=0,count=0,decieq,choice; int driver=DETECT,mode; /*functions for begining gui*/ struct stars { int x,y,x1,y1,z,c; }STARS[N]; void init() { int i,t; for(i=0;i<N;i++) { STARS[i].c=2; STARS[i].x = random(640); STARS[i].y = random(460); STARS[i].x1= random(320); STARS[i].y1= random(220); t=random(325); if(t==0) STARS[i].z=t+random(25)+1;//TO AVOID ERROR(division by 0) else STARS[i].z=t; } } void draw() { int i; for(i=0;i<N;i++) { if(STARS[i].y<480) putpixel(STARS[i].x,STARS[i].y,STARS[i].c); } } void erase() { int i; for(i=0;i<N;i++) putpixel(STARS[i].x,STARS[i].y,0); //putting black //color at stars position } /* if you use z+=2 stars will go away from you , but remember to change the condition :- if(STARS[i].z<1) {STARS[i].z=325;} to if(STARS[i].z>325) {STARS[i].z=1;} */ void move() { int i; for(i=0;i<N;i++) { STARS[i].x=((STARS[i].x1 * 640)/STARS[i].z)+320;//320 x-origin STARS[i].y=((STARS[i].y1 * 300)/STARS[i].z) +220;//220 y-origin STARS[i].z-=2; if(STARS[i].z<1) STARS[i].z=325; else if(STARS[i].z<162) STARS[i].c=15; else STARS[i].c=7; } } void showstars() { int i; init(); while(!kbhit()) { setcolor(3); //3 for cyan settextstyle(1,0,3); outtextxy(230,5,"PROJECT ON"); settextstyle(10,0,3); setcolor(i); outtextxy(170,30,"MULTIPLEXERS"); setcolor(5); settextstyle(1,0,3); move(); draw(); delay(15); erase(); i++; } closegraph(); restorecrtmode(); } void welcome() { int i, j, x, y, color; int MaxColors; struct palettetype palette; struct viewporttype vp; int height, width; initgraph(&driver,&mode,"f:\tc\bgi"); MaxColors = getmaxcolor() + 1; textcolor(4+BLINK); printf(" WELCOME"); textcolor(15); getpalette( &palette ); setviewport(0,50,630,470,1); getviewsettings( &vp ); width = (vp.right - vp.left) / 15; //width height = (vp.bottom - vp.top) / 10; // height x = y = 0; // Start in upper corner color = 1; // Begin at 1st color for( j=0 ; j<10 ; ++j ) { // 10 rows of boxes for( i=0 ; i<15 ; ++i ) { // 15 columns setfillstyle( SOLID_FILL, color++ );//Set the color bar( x, y, x+width, y+height ); // Draw the box x += width + 1; // Advance to next col color = 1 + (color % (MaxColors - 2));// Set new color } // End of i loop x = 0; // Goto 1st column y += height + 1; // Goto next row } // End of j loop while( !kbhit() ) // Until a key is hit setpalette( 1+random(MaxColors - 2), random( 65 ) ); setallpalette( &palette ); getch(); closegraph(); restorecrtmode(); initgraph(&driver,&mode,"f:\tc\bgi"); showstars(); } /*begining gui ends.text mode begins*/ /*multiplexer functions*/ void message(int num) //gives a message to user { //everytime select input is entered printf(" Only first %d select inputs considered.rest rejected(if any) ",num); } int check(int num) //For checking that a particular no. { //is present in function or not int ctr2; for(ctr2=0;ctr2<count;ctr2++) if(function[ctr2]==num) return (1); //true return(0); //false } void check_invalid_strobe(int ctr2) //for checking invalid select input { if(strobe[ctr2]>1 || strobe[ctr2]<0) { printf(" Invalid select input"); exit(2); } } void decide_output(int count) //decides whether output is 1 or 0 { //for normal mux implementation int ctr2; for(ctr2=0;ctr2<count;ctr2++) { if(decieq==function[ctr2]) { output = 1; break; } } } void decide_complex_inputs(int num) //decides inputs of a Mux which { //implements a function of a higher //level Mux int ctr2; for(ctr2=0;ctr2<num;ctr2++) { if(check(ctr2)) { if(check(ctr2+num)) inputs[ctr2]=1; else { inputs[ctr2]=!(strobe[0]); store[ctr2] = 0; } } else { if(check(ctr2+num)) { inputs[ctr2]=strobe[0]; store[ctr2] = 1; } else inputs[ctr2]=0; } } } void display_complex_input(int num) //displays inputs of a Mux which { //implements a function of a higher //level Mux int i; for(i=0;i<num;i++) { if(store[i]==0) printf(" Input %d = %s(%d)",i,"a bar",inputs[i]); else if(store[i]==1) printf(" Input %d = %c(%d)",i,'a',inputs[i]); else printf(" Input %d = %d",i,inputs[i]); } } void take_input(int num) //for taking select input in normal Mux { int ctr2; printf(" Enter the select input: "); for(ctr2=0;ctr2<num;ctr2++) { scanf("%d",&strobe[ctr2]); check_invalid_strobe(ctr2); } } void take_input_a(int num) //for taking input a in case of complex { //implementation of a function printf(" Enter the value of a(MSB of select input for %d:1) : ",num); scanf("%d",&strobe[0]); check_invalid_strobe(0); printf(" Only one value of MSB considered.rest rejected(if any) "); } void take_complex_select_input(int num) { int ctr2; printf(" Enter the select input: "); for(ctr2=1;ctr2<num;ctr2++) { scanf("%d",&strobe[ctr2]); check_invalid_strobe(ctr2); } printf(" Only first %d select inputs considered.rest rejected(if any)",num-1); printf(" Press any key to continue...."); getch(); } void display_output() { printf(" Output is : %d",output); printf(" Input %d is selected as output.",decieq); printf(" Press any key to continue....."); getch(); } void display_complex_output() { output = inputs[decieq]; printf(" Output is: %d",output); printf(" Input %d is selected as output.",decieq); printf(" Press any key to continue...."); getch(); } void two_is_to_one() { take_input(1); message(1); decieq = strobe[0]*1; decide_output(count); display_output(); } void four_is_to_one() { int ctr2; take_input(2); message(2); decieq = strobe[0]*2 + strobe[1]*1; decide_output(count); display_output(); } void eight_is_to_one() { int ctr2; take_input(3); message(3); decieq = strobe[0]*4 + strobe[1]*2 + strobe[2]*1; decide_output(count); display_output(); } void sixteen_is_to_one() { int ctr2; take_input(4); message(4); decieq = strobe[0]*8 + strobe[1]*4 + strobe[2]*2 + strobe[3]*1; decide_output(count); display_output(); } void thirtytwo_is_to_one() { int ctr2; take_input(5); message(5); decieq = strobe[0]*16 + strobe[1]*8 + strobe[2]*4 + strobe[3]*2 + strobe[4]*1; decide_output(count); display_output(); } void complex_two_is_to_one() { int ctr2; take_input_a(4); take_complex_select_input(2); message(1); decide_complex_inputs(2); decieq = strobe[1]*1; clrscr(); display_complex_input(2); display_complex_output(); } void complex_four_is_to_one() { int ctr2; take_input_a(8); take_complex_select_input(3); message(2); decide_complex_inputs(4); decieq = strobe[1]*2 + strobe[2]*1; clrscr(); display_complex_input(4); display_complex_output(); } void complex_eight_is_to_one() { int ctr2; take_input_a(16); take_complex_select_input(4); message(3); decide_complex_inputs(8); decieq = strobe[1]*4 + strobe[2]*2 + strobe[3]*1; clrscr(); display_complex_input(8); display_complex_output(); } void complex_sixteen_is_to_one() { int ctr2; take_input_a(32); take_complex_select_input(5); message(4); decide_complex_inputs(16); decieq = strobe[1]*8 + strobe[2]*4 + strobe[3]*2 + strobe[4]*1; clrscr(); display_complex_input(16); display_complex_output(); } /*multiplexing functions end*/ /*circuit gui*/ void common_gui(int num) { int y[32],i,i2,k; double j=log(num)/log(2); char str[2]; int stepsize=((280+num*3)-180)/(j+1); for(i=0;i<32;i++) y[i]=80 + (i+1)*10; initgraph(&driver,&mode,"f:\tc\bgi"); outtextxy(20,5,"RED: logic level 1"); outtextxy(250,5,"Press any key to continue....."); outtextxy(20,15,"GREEN:logic level 0"); for(i=0;i<num;i++) { if(check(i)) { setcolor(WHITE); circle(150,y[i],2); setfillstyle(SOLID_FILL,RED); floodfill(150,y[i],WHITE); } else { setcolor(15); circle(150,y[i],2); setfillstyle(SOLID_FILL,GREEN); floodfill(150,y[i],WHITE); } line(154,y[i],180,y[i]); } rectangle(180,40,280+num*3,y[i-1]+40); line(280+num*3,(y[i-1]-40)/2 + 60,280+3*num+40,(y[i-1]-40)/2 + 60); if(output==1) { setcolor(15); circle(280+num*3+44,(y[i-1]-40)/2 + 60,4); setfillstyle(SOLID_FILL,RED); floodfill(280+num*3+44,(y[i-1]-40)/2 + 60,WHITE); } else { setcolor(15); circle(280+num*3+44,(y[i-1]-40)/2 + 60,4); setfillstyle(SOLID_FILL,GREEN); floodfill(280+num*3+44,(y[i-1]-40)/2 +60,WHITE); } outtextxy(280+num*3+50,(y[i-1]-40)/2 + 60," Y(Output = )"); itoa(output,str,10); outtextxy(280+num*3+150,(y[i-1]-40)/2 + 60,str); itoa(num,str,10); outtextxy(140,y[i-1]+72," Block Diagram of "); outtextxy(290,y[i-1]+72,str); outtextxy(293,y[i-1]+72," : 1 Mux"); outtextxy((280+num*3-180)/2 + 150,y[(i-1)/2],str); outtextxy((280+num*3-180)/2 + 160,y[(i-1)/2]," : 1"); outtextxy((280+num*3-180)/2 + 150,y[(i-1)/2+2]," MUX"); outtextxy(280+num*3+170,(y[i-1]-40)/2 + 60,"(I "); itoa(decieq,str,10); outtextxy(280+num*3+185,(y[i-1]-40)/2 + 60,str); outtextxy(280+num*3+192,(y[i-1]-40)/2 + 60," )"); outtextxy(130,y[0]-5,"I0"); itoa(num-1,str,10); outtextxy(126,y[i-1],"I"); outtextxy(133,y[i-1],str); for(i2=0;i2<j;i2++) for(k=0;k<20;k++) { line(180+(i2+1)*stepsize,y[i-1]+40,180+(i2+1)*stepsize,y[i-1]+60); if(strobe[i2]==0) { setcolor(15); circle(180+(i2+1)*stepsize,y[i-1]+62,2); setfillstyle(SOLID_FILL,2); floodfill(180+(i2+1)*stepsize,y[i-1]+62,15); } else { setcolor(15); circle(180+(i2+1)*stepsize,y[i-1]+62,2); setfillstyle(SOLID_FILL,4); floodfill(180+(i2+1)*stepsize,y[i-1]+62,15); } } outtextxy(185+(i2)*stepsize,y[i-1]+62,"S0"); itoa(j-1,str,10); outtextxy(162+stepsize,y[i-1]+62,"S "); outtextxy(170+stepsize,y[i-1]+62,str); if(num==2) { setcolor(0); outtextxy(162+stepsize,y[i-1]+62,"S0"); setcolor(15); } getch(); } void common_complex_gui(int num) { int y[32],i,i2,k; double j=log(num)/log(2); char str[2]; int stepsize=((280+num*3)-180)/(j+1); for(i=0;i<32;i++) y[i]=80 + (i+1)*10; initgraph(&driver,&mode,"f:\tc\bgi"); outtextxy(20,5,"RED: logic level 1"); outtextxy(250,5,"Press anu key to continue....."); outtextxy(20,15,"GREEN:logic level zero"); for(i=0;i<num;i++) { if(inputs[i]==1) { setcolor(WHITE); circle(150,y[i],2); setfillstyle(SOLID_FILL,RED); floodfill(150,y[i],WHITE); } else { setcolor(15); circle(150,y[i],2); setfillstyle(SOLID_FILL,GREEN); floodfill(150,y[i],WHITE); } line(154,y[i],180,y[i]); } rectangle(180,40,280+num*3,y[i-1]+40); line(280+num*3,(y[i-1]-40)/2 + 60,280+3*num+40,(y[i-1]-40)/2 + 60); if(output==1) { setcolor(15); circle(280+num*3+44,(y[i-1]-40)/2 + 60,4); setfillstyle(SOLID_FILL,RED); floodfill(280+num*3+44,(y[i-1]-40)/2 + 60,WHITE); } else { setcolor(15); circle(280+num*3+44,(y[i-1]-40)/2 + 60,4); setfillstyle(SOLID_FILL,GREEN); floodfill(280+num*3+44,(y[i-1]-40)/2 +60,WHITE); } outtextxy(280+num*3+50,(y[i-1]-40)/2 + 60," Y(Output = )"); itoa(output,str,10); outtextxy(280+num*3+150,(y[i-1]-40)/2 + 60,str); itoa(num,str,10); outtextxy(140,y[i-1]+72," Block Diagram of "); outtextxy(290,y[i-1]+72,str); outtextxy(293,y[i-1]+72," : 1 Mux"); outtextxy((280+num*3-180)/2 + 150,y[(i-1)/2],str); outtextxy((280+num*3-180)/2 + 160,y[(i-1)/2]," : 1"); outtextxy((280+num*3-180)/2 + 150,y[(i-1)/2+2]," MUX"); outtextxy(280+num*3+170,(y[i-1]-40)/2 + 60,"(I "); itoa(decieq,str,10); outtextxy(280+num*3+185,(y[i-1]-40)/2 + 60,str); outtextxy(280+num*3+192,(y[i-1]-40)/2 + 60," )"); outtextxy(130,y[0]-5,"I0"); itoa(num-1,str,10); outtextxy(126,y[i-1],"I"); outtextxy(133,y[i-1],str); for(i2=1;i2<=j;i2++) for(k=0;k<20;k++) { line(180+(i2)*stepsize,y[i-1]+40,180+(i2)*stepsize,y[i-1]+60); if(strobe[i2]==0) { setcolor(15); circle(180+(i2)*stepsize,y[i-1]+62,2); setfillstyle(SOLID_FILL,2); floodfill(180+(i2)*stepsize,y[i-1]+62,15); } else { setcolor(15); circle(180+(i2)*stepsize,y[i-1]+62,2); setfillstyle(SOLID_FILL,4); floodfill(180+(i2)*stepsize,y[i-1]+62,15); } } outtextxy(185+(i2-1)*stepsize,y[i-1]+62,"S0"); itoa(j-1,str,10); outtextxy(162+stepsize,y[i-1]+62,"S "); outtextxy(170+stepsize,y[i-1]+62,str); if(num==2) { setcolor(0); outtextxy(162+stepsize,y[i-1]+62,"S0"); setcolor(15); } getch(); } /*circuit gui ends*/ /*main function*/ void main() { int ctr=0; welcome(); clrscr(); printf(" Prog to implement a function using a multiplexer logic:-"); printf(" Enter the function in minterms only."); printf(" Enter the function in form a b c d where a<b<c<d."); printf(" Press enter or provide spaces after each input."); printf(" Any value in input function cannot be repeated."); printf(" Enter the select input in form of 1's & 0's."); printf(" All the entered inputs are assumed to be high."); printf(" Maximun value of the minterm that can be accepted :31 "); textcolor(4+BLINK); textbackground(3); cprintf("Press any key to continue......."); textcolor(15); textbackground(0); getch(); printf(" How many input will you provide: "); scanf("%d",&count); if(count>32) { printf(" Invalid function input.inputs can't be greater than 32"); exit(1); } clrscr(); printf("Enter the function to be implemented : "); for(ctr=0;ctr<count;ctr++) { scanf("%d",&function[ctr]); if(function[ctr]>31) { printf(" Invalid function input"); exit(1); } } printf(" Only first %d inputs considered.rest rejected(if any)",count); fflush(stdin); if(function[count-1] <= 1) { two_is_to_one(); common_gui(2); } else if(function[count-1] <= 3) { label1: printf(" Implement using:- 1.)4:1 Mux 2.)2:1 Mux Enter your choice?"); scanf("%d",&choice); switch(choice) { case 1: four_is_to_one(); common_gui(4); break; case 2: complex_two_is_to_one(); common_complex_gui(2); break; default : printf(" Invalid choice"); goto label1; } } else if(function[count-1] <= 7) { label2: printf(" Implement using:- 1.)8:1 Mux 2.)4:1 Mux Enter your choice?"); scanf("%d",&choice); switch(choice) { case 1: eight_is_to_one(); common_gui(8); break; case 2: complex_four_is_to_one(); common_complex_gui(4); break; default : printf(" Invalid choice"); goto label2; } } else if(function[count-1] <= 15) { label3: printf(" Implement using:- 1.)16:1 Mux 2.)8:1 Mux Enter your choice?"); scanf("%d",&choice); switch(choice) { case 1: sixteen_is_to_one(); common_gui(16); break; case 2: complex_eight_is_to_one(); common_complex_gui(8); break; default : printf(" Invalid choice"); goto label3; } } else if(function[count-1] <= 31) { label4: printf(" Implement using:- 1.)32:1 Mux 2.)16:1 Mux Enter your choice?"); scanf("%d",&choice); switch(choice) { case 1: thirtytwo_is_to_one(); common_gui(32); break; case 2: complex_sixteen_is_to_one(); common_complex_gui(16); break; default : printf(" Invalid choice"); goto label4; } } getch(); }

/* 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; }

/* 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; }

/* #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; }

/* 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; }

/* 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; }

/* basic c program by main() function example */ #include <stdio.h> #include <conio.h> main() { printf (" It is a main() function "); int fun2(); // jump to void fun1() function printf ("\n Finally exit from the main() function. "); } void fun1() { printf (" It is a second function. "); printf (" Exit from the void fun1() function. "); } int fun2() { void fun1(); // jump to the int fun1() function printf (" It is a third function. "); printf (" Exit from the int fun2() function. "); 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(); }

/* 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; }

/* 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; }

/* 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(); }

/* 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; }

/* 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; }

/* #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; }

/* 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; }

/* creating a user defined function addition() */ #include <stdio.h> int addition(int num1, int num2) { int sum; /* Arguments are used here*/ sum = num1+num2; /* Function return type is integer so we are returning * an integer value, the sum of the passed numbers. */ return sum; } int main() { int var1, var2; printf("Enter number 1: "); scanf("%d",&var1); printf("Enter number 2: "); scanf("%d",&var2); /* Calling the function here, the function return type * is integer so we need an integer variable to hold the * returned value of this function. */ int res = addition(var1, var2); printf ("Output: %d", res); return 0; }

/* read formatted data from stdin by scanf() function example */ #include <stdio.h> #include <stdlib.h> #include <string.h> int main(int argc, const char * argv[]) { /* Define temporary variables */ char name[10]; int age; int result; /* Ask the user to enter their first name and age */ printf("Please enter your first name and your age.\n"); /* Read a name and age from the user */ result = scanf("%s %d",name, &age); /* We were not able to parse the two required values */ if (result < 2) { /* Display an error and exit */ printf("Either name or age was not entered\n\n"); exit(0); } /* Display the values the user entered */ printf("Name: %s\n", name); printf("Age: %d\n", age); return 0; }

/* return the nearest integer value of the float/double/argument by round() math function code example */ #include <stdio.h> #include <math.h> int main() { //Define temporary variable float i=5.2,j=6.8; //calculate and display round value printf("round value of %f is: %f\n",i,round(i)); printf("round value of %f is: %f\n",j,round(j)); i=4.9, j=-3.8; //calculate and display round value printf("round value of %f is: %f\n",i,round(i)); printf("round value of %f is: %f\n",j,round(j)); return 0; }

/* change the color of drawing text by textcolor() function example */ #include <stdio.h> //to use 'textbackground' #include <conio.h> int main() { // setting the color of background textbackground(GREEN); textcolor(MAGENTA+BLINK); // message cprintf("Change the color to MAGENTA"); textcolor(RED); // message cprintf("Change the color to RED"); // setting the color of background textbackground(RED); // message cprintf("Change the background color to RED"); getch(); 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; }

/* convert integer to string (non-standard function) by itoa() function example */ #include <stdio.h> #include <math.h> #include <stdlib.h> char* itoa(int num, char* buffer, int base) { int current = 0; if (num == 0) { buffer[current++] = '0'; buffer[current] = '\0'; return buffer; } int num_digits = 0; if (num < 0) { if (base == 10) { num_digits ++; buffer[current] = '-'; current ++; num *= -1; } else return NULL; } num_digits += (int)floor(log(num) / log(base)) + 1; while (current < num_digits) { int base_val = (int) pow(base, num_digits-1-current); int num_val = num / base_val; char value = num_val + '0'; buffer[current] = value; current ++; num -= base_val * num_val; } buffer[current] = '\0'; return buffer; } int main() { int a = 123456; char buffer[256]; if (itoa(a, buffer, 10) != NULL) { printf("Input = %d, base = %d, Buffer = %s\n", a, 10, buffer); } int b = -2310; if (itoa(b, buffer, 10) != NULL) { printf("Input = %d, base = %d, Buffer = %s\n", b, 10, buffer); } int c = 10; if (itoa(c, buffer, 2) != NULL) { printf("Input = %d, base = %d, Buffer = %s\n", c, 2, buffer); } 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; }

/* write output directly to the console by cprintf() function example */ int x; do { { clrscr(); design(); t(); textcolor(WHITE); gotoxy(24,3); cprintf("\xDB\xDB\xDB\xDB\xB2 LYDIA'S DEPARTMENT STORE \xB2\xDB\xDB\xDB\xDB"); gotoxy(3,4); cprintf("--------------------------------------------------------------------------"); gotoxy(35,5); cprintf("MAIN MENU"); gotoxy(26,8); cprintf(" 1 - INFORMATION ABOUT PRODUCTS "); gotoxy(26,9); cprintf(" 2 - ENTER PURCHASE RECORDS "); gotoxy(26,10); cprintf(" 3 - ENTER PRODUCTS TO BE SALE "); gotoxy(26,11); cprintf(" 4 - SEARCH FOR RECORD "); gotoxy(26,12); cprintf(" 5 - DELETE RECORD FROM STORE DATABASE "); gotoxy(26,13); cprintf(" 6 - VIEW SALES , PURCHASE & PROFIT REPORT "); gotoxy(26,14); cprintf(" 7 - PRINT RECORDS "); gotoxy(26,15); cprintf(" 8 - BAR GRAPH OF QUANTITY / PROFIT "); gotoxy(26,16); cprintf(" 9 - RETRIEVE INFORMATION "); gotoxy(26,17); cprintf(" H - HELP "); gotoxy(26,18); cprintf(" E - EXIT "); gotoxy(26,23); // cprintf("ENTER YOUR CHOICE :: "); gotoxy(47,23); x=toupper(getch()); } }

/* 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; }

/* 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; }

/* change current background color in text mode by textbackground() function example. */ #include <stdio.h> //to use 'textbackground' #include <conio.h> int main() { // setting the color of background textbackground(GREEN); textcolor(MAGENTA+BLINK); // message cprintf("Change the background to GREEN"); textcolor(YELLOW); // message cprintf("Change the color to RED"); // setting the color of background textbackground(BLUE); // message cprintf("Change the background color to BLUE"); getch(); return 0; }

/* compute natural logarithm by log() math function code example */ #include <stdio.h> #include <math.h> int main(int argc, const char * argv[]) { /* Define temporary variables */ double value; double result; /* Assign the value we will calculate the log of */ value = 1.5; /* Calculate the log of the value */ result = log(value); /* Display the result of the calculation */ printf("The Natural Logarithm of %f is %f\n", value, result); return 0; }

/* 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; }

/* 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" ); } }

/* 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; }

/* 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; }

/* 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; }

/* 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; }

/* 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; }

/* 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 ); }

/* 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); } } }

/* clear the screen and moves the cursor to the upper left-hand corner of the screen by clrscr() function example. */ #include <stdio.h> // clrscr() function definition void clrscr(void) { system("clear"); } int main() { clrscr(); //clear output screen printf("Hello World!!!"); //print message 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; }

/* 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); }

/* plot a pixel at location (x, y) of specified color by putpixel() 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; // initgraph initializes the // graphics system by loading a // graphics driver from disk initgraph(&gd, &gm, ""); // putpixel function putpixel(85, 35, GREEN); putpixel(30, 40, RED); putpixel(115, 50, YELLOW); putpixel(135, 50, CYAN); putpixel(45, 60, BLUE); putpixel(20, 100, WHITE); putpixel(200, 100, LIGHTBLUE); putpixel(150, 100, LIGHTGREEN); putpixel(200, 50, YELLOW); putpixel(120, 70, RED); getch(); // closegraph function closes the // graphics mode and deallocates // all memory allocated by // graphics system . closegraph(); 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; }