4-4

#include<stdio.h>
int main(void)
{
   int i,m;
        
   printf("Enter a number:");
   scanf("%d",&m);
   for(i=2;i<=m/2;i++)
       if(m%i==0)
           break;
   if(i>m/2&&m!=1)
       printf("%d is a prime number!\n",m);
   else
       printf("No!\n");

   return 0;
}