Example 1 - C hello world program
/* A very simple c program printing a string on screen*/
#include <stdio.h>
main()
{
printf("Hello World\n");
return 0;
}
Output of above program:
"Hello World"
Example 2 - c program to take input from user using scanf
#include <stdio.h>
main()
{
int number;
printf("Enter an integer\n");
scanf("%d",&number);
printf("Integer entered by you is %d\n", number);
return 0;
}
Output:
Enter a number
5
Number entered by you is 5
Example 3 - using if else control instructions
#include <stdio.h>
main()
{
int x = 1;
if ( x == 1 )
printf("x is equal to one.\n");
else
printf("For comparison use == as = is the assignment operator.\n");
return 0;
}
Output:
x is equal to one.
Example 4 - loop example
#include <stdio.h>
main()
{
int value = 1;
while(value<=3)
{
printf("Value is %d\n", value);
value++;
}
return 0;
}
Output:
Value is 1
Value is 2
Value is 3
Example 5 - c program for prime number
#include <stdio.h>
main()
{
int n, c;
printf("Enter a number\n");
scanf("%d", &n);
if ( n == 2 )
printf("Prime number.\n");
else
{
for ( c = 2 ; c <= n - 1 ; c++ )
{
if ( n % c == 0 )
break;
}
if ( c != n )
printf("Not prime.\n");
else
printf("Prime number.\n");
}
return 0;
}
Example 6 - command line arguments
#include <stdio.h>
main(int argc, char *argv[])
{
int c;
printf("Number of command line arguments passed: %d\n", argc);
for ( c = 0 ; c < argc ; c++)
printf("%d. Command line argument passed is %s\n", c+1, argv[c]);
return 0;
}
Above c program prints the number and all arguments which are passed to it.
Example 7 - Array program
#include <stdio.h>
main()
{
int array[100], n, c;
printf("Enter the number of elements in array\n");
scanf("%d", &n);
printf("Enter %d elements\n", n);
for ( c = 0 ; c < n ; c++ )
scanf("%d", &array[c]);
printf("Array elements entered by you are:\n");
for ( c = 0 ; c < n ; c++ )
printf("array[%d] = %d\n", c, array[c]);
return 0;
}
Example 8 - function program
#include <stdio.h>
void my_function();
main()
{
printf("Main function.\n");
my_function();
printf("Back in function main.\n");
return 0;
}
void my_function()
{
printf("Welcome to my function. Feel at home.\n");
}
Example 9 - Using comments in a program
#include <stdio.h>
main()
{
// Single line comment in c source code
printf("Writing comments is very useful.\n");
/*
* Multi line comment syntax
* Comments help us to understand code later easily.
* Will you write comments while developing programs ?
*/
printf("Good luck c programmer.\n");
return 0;
}
Example 10 - using structures in c programming
#include <stdio.h>
struct programming
{
float constant;
char *pointer;
};
main()
{
struct programming variable;
char string[] = "Programming in Software Development.";
variable.constant = 1.23;
variable.pointer = string;
printf("%f\n", variable.constant);
printf("%s\n", variable.pointer);
return 0;
}
Example 11 - c program for Fibonacci series
#include <stdio.h>
main()
{
int n, first = 0, second = 1, next, c;
printf("Enter the number of terms\n");
scanf("%d",&n);
printf("First %d terms of Fibonacci series are :-\n",n);
for ( c = 0 ; c < n ; c++ )
{
if ( c <= 1 )
next = c;
else
{
next = first + second;
first = second;
second = next;
}
printf("%d\n",next);
}
return 0;
}
Example 12 - c graphics programming
#include <graphics.h>
#include <conio.h>
main()
{
int gd = DETECT, gm;
initgraph(&gd, &gm,"C:\\TC\\BGI");
outtextxy(10,20, "Graphics source code example.");
circle(200, 200, 50);
setcolor(BLUE);
line(350, 250, 450, 50);
getch();
closegraph( );
return 0;
}
