a to the power b using log n

Generate A to power B

int power(int a, int b) {
    if (b == 0)
        return 1;
    if (b == 1)
        return a;
    if (b<0)
        return 1/power(a, -b); // a should not be 0
    int x = power(a, b/2);
    return b&1? x*x*a:x*x;
}