在C++中一些小问题

1.记录程序运行时间

<span style="font-size:18px;">#include "time.h"

using namespace std;

int main(){
clock_t start, finish;
double time_length;
start = clock();//start存储的是当前的时刻
.......................
finish = clock();//finish存储的是结束的时刻
time_length = (double)(finish - start) / CLOCKS_PER_SEC;//根据两个时刻的差，计算出运行的时间

cout<<"Time used is "<<time_length<<" second."<<endl;

return 0;
}</span>

CLOCKS_PER_SEC:是为了把时间转换为秒 ：  C++中   #define
CLOCKS_PER_SEC  1000

2.计算x的y次方

<span style="font-size:18px;">#include <iostream.h>
#include <math.h>//记得包含
void main()
{ int n,m;
.......
......
....
m=pow(x,y);
.....
}</span>

未完待续