剑指Offer09 数值的整数次方

/*************************************************************************
    > File Name: 09_Power.c
    > Author: Juntaran
    > Mail: JuntaranMail@gmail.com
    > Created Time: 2016年08月29日 星期一 21时07分21秒
 ************************************************************************/

#include <stdio.h>
 
double Power(double base, int exponent)
{
    if (base == 0)
        return 0;
    if (exponent == 0)
        return 1;
    if (exponent == 1)
        return base;
    
    int x = abs(exponent);
    double r = 1.0;
    
    while (x)
    {
        if (x & 1)
            r *= base;
        base *= base;
        x >>= 1;
        printf("r is %f
 base is %f
 x is %d
", r, base, x);
    }
    return exponent<0 ? 1/r : r;
}

int main()
{
    double base = 2;
    int exponent = 10;
    double ret = Power(base, exponent);
    printf("ret is %f
", ret);
    
    return 0;
}