Break if any key is pressed c++

Question

I want to break out of a while loop if the User pressed any key during a Sleep(miliseconds), as in stop if any key is pressed during those miliseconds. How do I do that? The loop looks like this:

while (1)
{
    r = rand() % 5501 + 1000;
    Sleep(r);
    cout << "NOW!\n";
    t = clock() / 1000;
    system("pause");
    if (clock() / 1000 < t + 1)
    {
        cnt++;
        cout << "Aaaaand...\n";
    }
    else break;
}

Platform: Windows

It depends on the capabilities of your terminal and operating system. There's no C++ language function for that. — David Schwartz, Nov 18 '16 at 09:26
Something like http://stackoverflow.com/questions/1449324/how-to-simulate-press-any-key-to-continue — RvdK, Nov 18 '16 at 09:27
Something like http://stackoverflow.com/questions/3157295/interrupt-sleep-function is a good start to understand how to sleep could be interrupted — Fefux, Nov 18 '16 at 09:33
Instead of awaiting user input, I want to keep it as a condition for breaking out of the while loop — Cosmin Petolea, Nov 18 '16 at 09:33
Why don't you use of thread? One thread wait for user input and start another which perform other part when user press a key? (I know it's not the question) — Fefux, Nov 18 '16 at 09:42
You should edit question and add the platform tag (Windows, Linux) — kebs, Nov 18 '16 at 09:52

score 3 · Answer 1 · answered Nov 18 '16 at 09:45

There is no C++ language solution to do this.

You will have to find a platform specific function which waits until there is input available with a timeout. Call that function instead of Sleep (which is also not a C++ function). On return from that function check the return code to see if it returned because there is input available (user pressed a key), or timed out (user didn't press a key).

score 2 · Accepted Answer · answered Nov 18 '16 at 20:33

You can use kbhit(). Try this:

bool exit = false;
while(!exit){
    if(kbhit())
         exit = true;
}

This'll work if you're working with windows. If you are with linux you can also copy paste kbhit.h y kbhit.cpp from http://linux-sxs.org/programming/kbhit.html and add it to your project.

Break if any key is pressed c++

2 Answers2

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