Program to find whether the number is power of 2 or not?

//without  using  functions.

#include <stdio.h>
#include <conio.h>

int main()
{
    int num, rem, flag=0;
    printf ("\n Enter a Number: ");
    scanf ("%d", &num);
   
    while(num > 2)
    {
        rem = num % 2;
        if( rem == 1 )
        {
            flag = 1;
            break;
        }
        else
        num = num/2;
    }
   
    if( flag == 1 )
    {
        printf("\n Number is not Power of two.");
    }
    else
    {
        printf("\n Number is Power of two");
    }
}