To check whether a number is prime or not

check_prime.c

/**
  * To check whether a number is prime or not
  **/

#include<stdio.h>
#include<stdlib.h>

int main(void)
{
  int n, i, p = 1;

  printf("Enter any number:");
  scanf("%d", &n);

  /* 0 and 1 are neither a prime nor a composite number */
  if((n == 0) || (n == 1)) {
    printf("The number is neither prime nor composite\n");
    exit(0);
  }

  /* 2 is a prime number */
  if(n == 2) {
    printf("The number is prime\n");
    exit(0);
  }

  /* Check for all numbers other than 0, 1 and 2 */
  for(i = 2; i < n/2; i++)
    if(n % i == 0) {
      printf("Number is a composite number\n");
      p = 0;
    }
  if(p == 1)
    printf("The number is prime\n");

  return 0;
}