The floating point version will work for integers up to about 2^51
(the width of mantissa). Beyond that integers cannot be represented
with perfect precision and will give you all the nastiness people have
pointed out.
A simple O(logn) implementation -
int64 pow_int64(int64 base, int64 pow) {
if (pow == 0) return 1;
int64 t = pow_int64(base, pow / 2);
if (pow % 2 == 1) return base*t*t;
else return t*t;
}
This is the recursive version. Can easily be converted to iterate
instead.
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