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Prime number tester


#include <stdio.h>

int main(void)
{
  int num, i, is_prime;

  printf("Enter a number: ");
  scanf("%d", &num);

  
  is_prime = 1;
  
  for(i = 2; i <= num / 2; i = i + 1)
    if((num%i)==0) 
         is_prime = 0;

  if(is_prime==1) 
      printf(" is prime.");
  else 
      printf("not prime.");

  return 0;
}








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