How to check if a number is a power of 2

Question

Today I needed a simple algorithm for checking if a number is a power of 2.

The algorithm needs to be:

1. Simple
2. Correct for any ulong

Answer 1

Find if the given number is a power of 2.

#include 

int main(void)
{
    int n,logval,powval;
    printf("Enter a number to find whether it is s power of 2\n");
    scanf("%d",&n);
    logval=log(n)/log(2);
    powval=pow(2,logval);

    if(powval==n)
        printf("The number is a power of 2");
    else
        printf("The number is not a power of 2");

    getch();
    return 0;
}