Exhaustive method to determine whether the entered number is a prime number

#include <stdio.h>

int main(int argc, char *argv[])
{
    int num,i;
     bool flag = true ;     /* initialization judgment result */ 

    scanf( " Please enter a real number:%d " ,&num); /* Accept a real number */

    for (i= 2 ;i<num;i++) /* Exhaustive judgment */
    {
        if(num % i==0)
        {
            flag = false ;     /* Not a prime number */ 
            break ;
        }
    }

    if(flag==true&&num%1==0&&num%num==0)
    {
        printf( " is a prime number " )
    }
    else
    {
        printf( " Not a prime number " )
    }

}