/*
 * 计算数值的整数次方.cpp
 *
 *  Created on: 2018年4月13日
 *      Author: soyo
 */
#include<iostream>
#include<math.h>
#include<ctime>
using namespace std;
int main()
{
    double power(double base,int exp);
    int x=2,y=3;
    long int z;
    z=pow(2,3);
    cout<<"值为:"<<z<<endl;
    z=z>>2;//右移两位
    cout<<"值为:"<<z<<endl;
    double a;
    clock_t start,stop,consume_time;
    start=clock();
    a=power(12,100);
    stop=clock();
    consume_time=stop-start;
    cout<<"新值为:"<<a<<endl;
    cout<<"运行时间为:"<<consume_time<<endl;
}
double power(double base,int exp)
{
    if(exp==0)
        return 1;
    if(exp==1)
        return base;
    double result;
     result=power(base,exp>>1);
     result*=result;
     if(exp&0x1==1)
         result*=base;
//     if(exp%2==1)      //都可以（但第一种效率更高)
//         result*=base;
     return result;
}

值为:8
值为:2
新值为:8.2818e+107
运行时间为:1