如何在 C++ 中使用计时器在给定时间内强制输入? [英] How to use a timer in C++ to force input within a given time?

问题描述

我想在 C++ 中实现超时功能.

I want to implement a time out feature in C++.

如果用户在 2 秒内没有输入值，那么程序必须显示超时语句并再次要求输入

If the user does not input the value within 2 seconds then the program must display the time-out statement and ask the input again

EX(输出屏幕):

Timer=0;  
Please enter the input:       //if input is not given within 2 seconds then  
Time-out: 2 seconds  
Timer again set to 0  
Please enter the input:  //if input is not given within 2 seconds then  
Time-out: 2 seconds  
Timer again set to 0  
Please enter the input:22  
Data accepted  
Terminate the program`

代码:

#include<iostream>  
 #include<time.h>  
 using namespace std;  
 int main()  
{  
    clock_t endwait;  
    endwait =  2000 ;  
   cout<<endwait;  
   while (clock() < endwait)  
  {  
         cout<<"Please enter the input:";  
  }  
   return 0;  
} 

我已经研究了上面的代码.但这只会在进入 WHILE 循环时发生.我该如何做才能获得所需的输出.

I have worked on the above code. But this happens only while entering the WHILE loop. How shall i do it in a way so that, I get the required output.

推荐答案

#include <iostream>
#include <thread>
#include <chrono>
#include <mutex>
#include <condition_variable>
using namespace std;
condition_variable cv;

int value;

void read_value() {
    cin >> value;
    cv.notify_one();
}

int main()
{
    cout << "Please enter the input: ";
    thread th(read_value);

    mutex mtx;
    unique_lock<mutex> lck(mtx);
    while (cv.wait_for(lck, chrono::seconds(2)) == cv_status::timeout)
    {
        cout << "
Time-Out: 2 second:";
        cout << "
Please enter the input:";
    }
    cout << "You entered: " << value << '
';

    th.join();

    return 0;
}

输出:

Please enter the input:  
Time-Out: 2 second:  
Please enter the input:  
Time-Out: 2 second:  
Please enter the input:22  
You entered: 22  

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