C Program to check if a number is prime or not

Algorithm

Input: Input a numbers
output: Check if a number is prime or not

1. Start
2. Input a numbers say n
3. i = 2
4. check =0
5. while ( i < = n/2) repeat 5.1 & 5.2
   5.1 if (n % i == 0) 
      5.1.1 check++
   5.2 i++
6. if ( check == 0)
   6.1 Print prime
7. else
   7.1 Print not prime
8. stop

C Program

#include <stdio.h>

int main( )

{

   int n, check = 0;

   printf("Enter a number: ");

   scanf("%d", &n);

   for (int i = 2; i <= n / 2; i++)

    {

       if (n % i == 0)

            check++;

    }

    if (check == 0)

        printf("The number %d is prime", n);

    else

        printf("The number %d is not prime", n);

   return 0;

}