如何在 C++ 中初始化时间点并将它们设置为假值？

Question

我是 C++ 的新手，我想实现以下行为。

#include <thread>
#include <chrono>
#include <iostream>

using namespace std;

int main(){
    chrono::high_resolution_clock::time_point start_time_point;
    while(true){
      if(statement_1){
         // check whether start_time_point is falsy
         if(...) start_time_point = chrono::high_resolution_clock::now();
         auto current_time_point = chrono::high_resolution_clock::now();
         if(chrono::duration_cast<std::chrono::seconds>(current_time_point - start_time_point).count() > 5) {
            // do something
         }
      }

      if(statement_2){
         // assign some falsy value to start_time_point
         // so that next time the first if block is entered a new time point is assigned to start_time_point
      }
   }

}

我习惯了javascript，所以在JS中我只会在第二个if块中将null赋值给start_time_point，但在C++中是不同的。我将如何实现上述行为？

Answer 1

I am used to javascript, so in JS I only would assign null to start_time_point in the second if block but in C++ it is different. How would I achieve the above-mentioned behavior?

一个chrono::time_point有一个min()成员，返回可能的最低时间点。它不完全相同，但可以 与 javascript.

中的空值相似

也许

start_time_point = start_time_point.min();

如何在 C++ 中初始化时间点并将它们设置为假值？

How initialize time points and set them to a falsy value afterward in C++?

c++

chrono