C language program to find Prime Number.

#include<stdio.h>

#include<math.h>

void main()

{

          int num,i,is_prime=0;

          clrscr();

          printf(" Give a number : ");

          scanf("%d",&num);

          for (i=2;i<=sqrt(num);i++)

          {

          if (num%i==0)

          {

          is_prime=1;

          break;

          }

          }

          if (is_prime==1)

          printf(" Not prime number");

          else

          printf(" Prime number");

          getch();

}