C/C++计时

Mar 31st, 2019 0

本文记录如何使用C/C++进行计时操作。

C

void timing()
{
    time_t start,stop;
    start = time(NULL);
    foo(); // do something
    stop = time(NULL);
    printf("Time:%ld\n",(stop-start));

    clock_t start2,stop2; // high resolution
    start2 = time(NULL);
    foo(); // do something
    stop2 = time(NULL);
    printf("Time:%f\n",(stop2-start2)/CLOCKS_PER_SEC);
}

C++

C++11中添加了<chrono>库，专门用来计时。

#include <iostream>
#include <chrono>
using std::chrono::high_resolution_clock Clock;

int main()
{
    auto t1 = Clock::now();
    auto t2 = Clock::now();
    std::cout << "Delta t2-t1: "
              << std::chrono::duration_cast<std::chrono::nanoseconds>(t2 - t1).count()
              << " nanoseconds" << std::endl;
}