C++下程序运行时间的四种常用计时方法总结

#include <time.h>　　　//引入头文件
int main()
{
clock_t start,end;　　　//定义clock_t变量
start = clock();  　　　//开始时间

fun()  //需计时的函数

end = clock();   //结束时间
cout<<"time = "<<double(end-start)/CLOCKS_PER_SEC<<"s"<<endl;  //输出时间（单位：ｓ）
}

#include <windows.h>　　　//引入头文件
int main()
{
    DWORD t1,t2;
    t1 = GetTickCount();

    fun()  //需计时的函数

    t2 = GetTickCount();
    cout<<"time = "<<((t2-t1)*1.0/1000)<<endl;  //输出时间（单位：ｓ）
}

#include <windows.h>　　　//引入头文件
int main()
{
    LARGE_INTEGER t1,t2,tc;
    QueryPerformanceFrequency(&tc);
    QueryPerformanceCounter(&t1);

    fun()  //需计时的函数

    QueryPerformanceCounter(&t2);
    time=(double)(t2.QuadPart-t1.QuadPart)/(double)tc.QuadPart; 
    cout<<"time = "<<time<<endl;  //输出时间（单位：ｓ）
}

//timeval结构定义为:
struct timeval{
long tv_sec; /*秒*/
long tv_usec; /*微秒*/
};
//timezone 结构定义为:
struct timezone{
int tz_minuteswest; /*和Greenwich 时间差了多少分钟*/
int tz_dsttime; /*日光节约时间的状态*/
};

#include <sys/time.h>　　　//引入头文件
int main()
{
    struct timeval t1,t2;
    double timeuse;
    gettimeofday(&t1,NULL);

    fun();

    gettimeofday(&t2,NULL);
    timeuse = (t2.tv_sec - t1.tv_sec) + (double)(t2.tv_usec - t1.tv_usec)/1000000.0;

    cout<<"time = "<<timeuse<<endl;  //输出时间（单位：ｓ）
}

    time_t start,stop;
    start = time(NULL);
    fun();
    stop = time(NULL);

import datetime
start = datetime.datetime.now()
run_function():
    # do something
end = datetime.datetime.now()
print (end-start

import time
start = time.time()
run_function()
end = time.time()
print str(end)

import time
start = time.clock()
run_function()
end = time.clock()
print str(end-start)