用log(N)的解法实现数值的整数次方

//
//  main.m
//  c++test
//
//  Created by andyyang on 6/3/13.
//  Copyright (c) 2013 andyyang. All rights reserved.
//
 
//#import <Foundation/Foundation.h>
#include "stdio.h"
#include "string.h"
 
int power(double base,int exponent)
{
 if(exponent==0)
 {
     return 1;
 }
    if(exponent==1)
    {
        return base;
    }
    if(exponent &0x01)
    {
        return power(base,exponent>>1)*power(base,exponent>>1)*base;
    }else
    {
        return power(base,exponent>>1)*power(base,exponent>>1);
    }
}
int main(int argc, const char * argv[])
{
    double ret=power(12, 2);
    printf("%f",ret);
    getchar();
    return 0;
}

充分利用位运算，高效低实现数值的整数次方