Run the program until user input

[cbsestudent]

Hello everybody,
I've had a doubt. Is it possible to write a code such that the program keeps running till it detects some user input. It should run without any input and should stop running when the user types anything.

#include<iostream>
#include <time.h>
#include<stdlib.h>
 void sleep(unsigned int mseconds)
{
    clock_t goal = mseconds + clock();
    while (goal > clock());
}
using namespace std;
int main()
{
    int Hour,Minute,second,i=1;

        cout<<"Enter the hour : ";
        cin>>Hour;
        cout<<"Enter the minute : ";
        cin>>Minute;
        cout<<"Enter the second : ";
        cin>>second;
        do
        {
        cout<<"The time is "<<Hour<<":"<<Minute<<":"<<second<<endl;
        sleep(1000000);
        system("clear");
        second++;
        if (second>59)
        {
            Minute++;
            second=second-60;
        }
        if (Minute>59)
        {
            Hour++;
            Minute=Minute-60;
        }
        if (Hour>23)
        {
            Hour=Hour-24;
        }
        i++;
    }while(i<1000);
}

For example,in this code, I've set it to run 1000 times. But is it possible to make it run until the user types something ?

[JLBorges]

#include <iostream>
#include <chrono>
#include <future>
#include <ctime>

std::string now()
{
    const std::time_t t = std::time(nullptr) ;
    return std::ctime( std::addressof(t) ) ;
}

bool wait_for_user_input() { return std::cin.get() ; }

int main()
{
    std::cout << "press enter to quit\n" << std::endl ;

    // http://en.cppreference.com/w/cpp/thread/async
    const auto future = std::async( std::launch::async, wait_for_user_input ) ;

    do std::cout << now() << std::flush ;
    while( future.wait_for( std::chrono::seconds(1) ) == std::future_status::timeout ) ;
    // http://en.cppreference.com/w/cpp/thread/future/wait_for
}