Why isn't `int pow(int base, int exponent)` in the standard C++ libraries?

Question

I feel like I must just be unable to find it. Is there any reason that the C++ pow function does not implement the \"power\" function for anything except

Answer 1

Here's a really simple O(log(n)) implementation of pow() that works for any numeric types, including integers:

template
static constexpr inline T pown(T x, unsigned p) {
    T result = 1;

    while (p) {
        if (p & 0x1) {
            result *= x;
        }
        x *= x;
        p >>= 1;
    }

    return result;
}

It's better than enigmaticPhysicist's O(log(n)) implementation because it doesn't use recursion.

It's also almost always faster than his linear implementation (as long as p > ~3) because:

• it doesn't require any extra memory
• it only does ~1.5x more operations per loop
• it only does ~1.25x more memory updates per loop