C Programming Code Examples
C > Games and Graphics Code Examples
Program to Draw a Triangle using Graphics Function
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/* Program to Draw a Triangle using Graphics Function */
#include<stdio.h>
#include<conio.h>
#include<graphics.h>
void main() {
int gd = DETECT, gm;
initgraph(&gd, &gm, "c:\\tc\\bgi");
line(169, 88, 66, 88);
line(169, 88, 50, 88);
line(66, 44, 50, 44);
getch();
closegraph();
}
getch() Function in C
The getch() is a predefined non-standard function that is defined in conio.h header file. It is mostly used by the Dev C/C++, MS- DOS's compilers like Turbo C to hold the screen until the user passes a single value to exit from the console screen. It can also be used to read a single byte character or string from the keyboard and then print. It does not hold any parameters. It has no buffer area to store the input character in a program.
Syntax for getch() Function in C
#include <conio.h>
int getch(void);
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/* 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();
}
closegraph() Function in C
The header file graphics.h contains closegraph() function which closes the graphics mode, deallocates all memory allocated by graphics system and restores the screen to the mode it was in before you called initgraph.
closegraph() function is used to re-enter in the text mode and exit from the graphics mode. If you want to use both text mode and graphics mode in the program then you have to use both initgraph() and closegraph() function in the program.
Syntax for closegraph() Function in C
#include <graphics.h>
void closegraph();
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/* 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;
}
line() Function in C
line() is a library function of graphics.c in c programming language which is used to draw a line from two coordinates. line() function is used to draw a line from a point(x1,y1) to point(x2,y2) i.e. (x1,y1) and (x2,y2) are end points of the line.
Syntax for line() Function in C
#include <graphics.h>
void line(int x1, int y1, int x2, int y2);
x1
X coordinate of first point
y1
Y coordinate of first point.
x2
X coordinate of second point.
y2
Y coordinate of second point.
This is a predefined function named line which is used to draw a line on the output screen. It takes 4 arguments, first two parameters represent an initial point and the last two arguments are for the final points of the line.
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/* 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;
}
#include Directive in C
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program. Here are the two types of file that can be included using #include:
• Header File or Standard files: This is a file which contains C/C++ function declarations and macro definitions to be shared between several source files. Functions like the printf(), scanf(), cout, cin and various other input-output or other standard functions are contained within different header files. So to utilise those functions, the users need to import a few header files which define the required functions.
• User-defined files: These files resembles the header files, except for the fact that they are written and defined by the user itself. This saves the user from writing a particular function multiple times. Once a user-defined file is written, it can be imported anywhere in the program using the #include preprocessor.
Syntax for #include Directive in C
#include "user-defined_file"
#include <header_file>
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/* #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;
}
main() Function in C
In C, the "main" function is treated the same as every function, it has a return type (and in some cases accepts inputs via parameters). The only difference is that the main function is "called" by the operating system when the user runs the program. Thus the main function is always the first code executed when a program starts.
main() function is a user defined, body of the function is defined by the programmer or we can say main() is programmer/user implemented function, whose prototype is predefined in the compiler. Hence we can say that main() in c programming is user defined as well as predefined because it's prototype is predefined.
main() is a system (compiler) declared function whose defined by the user, which is invoked automatically by the operating system when program is being executed.
Its first function or entry point of the program from where program start executed, program's execution starts from the main. So main is an important function in c , c++ programming language.
Syntax for main() Function in C
void main()
{
.........
// codes start from here
.........
}
void
is a keyword in C language, void means nothing, whenever we use void as a function return type then that function nothing return. here main() function no return any value.
In place of void we can also use int return type of main() function, at that time main() return integer type value.
main
is a name of function which is predefined function in C library.
• An operating system always calls the main() function when a programmers or users execute their programming code.
• It is responsible for starting and ends of the program.
• It is a universally accepted keyword in programming language and cannot change its meaning and name.
• A main() function is a user-defined function in C that means we can pass parameters to the main() function according to the requirement of a program.
• A main() function is used to invoke the programming code at the run time, not at the compile time of a program.
• A main() function is followed by opening and closing parenthesis brackets.
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/* 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;
}
initgraph() Function in C
initgraph initializes the graphics system by loading a graphics driver from disk (or validating a registered driver), and putting the system into graphics mode. To start the graphics system, first call the initgraph function. initgraph loads the graphics driver and puts the system into graphics mode. You can tell initgraph to use a particular graphics driver and mode, or to autodetect the attached video adapter at run time and pick the corresponding driver.
If you tell initgraph to autodetect, it calls detectgraph to select a graphics driver and mode. initgraph also resets all graphics settings to their defaults (current position, palette, color, viewport, and so on) and resets graphresult to 0.
Normally, initgraph loads a graphics driver by allocating memory for the driver (through _graphgetmem), then loading the appropriate .BGI file from disk. As an alternative to this dynamic loading scheme, you can link a graphics driver file (or several of them) directly into your executable program file.
Syntax for initgraph() Function in C
#include <graphics.h>
void initgraph(int *graphdriver, int *graphmode, char *pathtodriver);
pathtodriver
pathtodriver specifies the directory path where initgraph looks for graphics drivers. initgraph first looks in the path specified in pathtodriver, then (if they are not there) in the current directory. Accordingly, if pathtodriver is null, the driver files (*.BGI) must be in the current directory. This is also the path settextstyle searches for the stroked character font files (*.CHR).
graphdriver
graphdriver is an integer that specifies the graphics driver to be used. You can give it a value using a constant of the graphics_drivers enumeration type, which is defined in graphics.h and listed below.
• DETECT – 0 (requests autodetect)
• CGA – 1
• MCGA – 2
• EGA – 3
• EGA64 – 4
• EGAMONO – 5
• IBM8514 – 6
• HERCMONO – 7
• ATT400 – 8
• VGA – 9
• PC3270 – 10
graphmode
graphmode is an integer that specifies the initial graphics mode (unless *graphdriver equals DETECT; in which case, *graphmode is set by initgraph to the highest resolution available for the detected driver). You can give *graphmode a value using a constant of the graphics_modes enumeration type, which is defined in graphics.h and listed below.
initgraph always sets the internal error code; on success, it sets the code to 0. If an error occurred, *graphdriver is set to -2, -3, -4, or -5, and graphresult returns the same value as listed below:
• grNotDetected: -2 Cannot detect a graphics card
• grFileNotFound: -3 Cannot find driver file
• grInvalidDriver: -4 Invalid driver
• grNoLoadMem: -5 Insufficient memory to load driver
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/* 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;
}
C Input base and height of a triangle and find area of the given triangle. How to find area of a triangle in C programming. Input base of the triangle. Store in some variable say base.
C program, 'using recursion', performs binary search. In this c program, an array of random number is generated. User is asked to enter a key. The array of random numbers are sorted
