C++时间日期相关

// 计时
#pragma once

#include <iostream>
#include <thread>
#include <chrono>
#include <ctime> // clock

namespace DS
{
    // 当n超过一定次数时，栈溢出，比如10万次时：0x005753E9 处有未经处理的异常(在 DS.exe 中): 0xC00000FD: Stack overflow 
    // 实际项目中慎用递归，实际项目中一般会设置最大递归次数，若到达最大递归次数哪怕没求得结果也要返回，防止程序栈破裂，程序终止
    void PrintN_Recursive(int n)
    {
        // 递归终止条件
        if (n <= 1) {
            return;
        }

        //std::cout << n << ' ';// 放在这就会逆序打印
        PrintN_Recursive(--n);
        std::cout << n << std::endl;
    }

    void PrintN_Loop(int n)
    {
        for (int i = 1; i <= n; ++i) {
            std::cout << i << std::endl;
        }
    }

    void PrintN_Test() 
    {
        clock_t start_time = 0, end_time = 0;
        int n = 0;
        std::cout << "Input N:";
        std::cin >> n;

        std::cout << "By loop:" << std::endl;
        start_time = clock();// C语言方式计时
        DS::PrintN_Loop(n);
        end_time = clock();
        std::cout << "duration:" << end_time - start_time << "ms" << std::endl;
        //std::cout << "duration:" << (end_time - start_time) / CLOCKS_PER_SEC << "s" << std::endl; // CLK_TCK或CLOCKS_PER_SEC是每秒走过的时钟打点数

        std::this_thread::sleep_for(std::chrono::milliseconds(3000));

        std::cout << "By Recursive:" << std::endl;
        auto start = std::chrono::steady_clock::now(); // C++11
        DS::PrintN_Recursive(n);// 当n超过一定次数时，栈溢出，比如1万次时：0x005753E9 处有未经处理的异常(在 DS.exe 中): 0xC00000FD: Stack overflow 
        auto end = std::chrono::steady_clock::now();
        auto dura = std::chrono::duration_cast<std::chrono::microseconds>(end - start).count();// 微妙
        std::cout << "duration:" << dura * 0.001  << "ms" << std::endl;
    }

}