How do you do exponentiation in C?

Question

I tried \"x = y ** e\", but that didn\'t work.

Answer 1

The non-recursive version of the function is not too hard - here it is for integers:

long powi(long x, unsigned n)
{
    long p = x;
    long r = 1;

    while (n > 0)
    {
        if (n % 2 == 1)
            r *= p;
        p *= p;
        n /= 2;
    }

    return(r);
}

(Hacked out of code for raising a double value to an integer power - had to remove the code to deal with reciprocals, for example.)