How to use Ctrl + D to activate EOF in C++?

Question

I've never used EOF before and I'm wondering how I could create a code that continues running until I press Ctrl+D to activate EOF. This is the general idea I have:

int main(){
    int num;
    while (!EOF) { //while the EOF is not activate
        cin >> num; //use cin to get an int from the user
        //repeatedly give feedback depending on what int the user puts in
        //activate EOF and end the while loop when the user presses "Ctrl + D"
    }
}

So how would I set it up to end when the user presses Ctrl+D? Thanks!

Possible dupe: https://stackoverflow.com/questions/25770335/while-loop-asking-for-input-until-ctrl-d-using-c — CinCout, Feb 03 '18 at 05:16
@CinCout: It's good for the questions to be linked, but the answers are different between C and C++, so they are not duplicates. — Ben Voigt, Feb 03 '18 at 05:32

Jon Deaton · Answer 1 · 2018-02-03T05:20:49.900

3

Try

int main(){
    int num;
    while (cin >> num) { 
       // ...
    }
}

edited Feb 03 '18 at 05:20

answered Feb 03 '18 at 05:15

Jon Deaton

3,943
6
28
41

2

please read https://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong – Ed Heal Feb 03 '18 at 05:15
@EdHeal Thank you. – Jon Deaton Feb 03 '18 at 05:19
1

My job is done for today - at lest you have learned something today :-) – Ed Heal Feb 03 '18 at 05:22
@EdHeal yeah, thanks I really appreciate that. Gonna go fix some bugs in my repositories now... – Jon Deaton Feb 03 '18 at 05:23

score 3 · Accepted Answer · answered Feb 03 '18 at 05:18

3

Here is a working example using integers and the EOF check.

#include <iostream>

int main(int argc, char *argv[]) {

  int num;

  for (;;) {

    std::cin >> num;
    if (std::cin.eof()) break;
    std::cout << "Number is " << num << std::endl;

  }

  return 0;

}

answered Feb 03 '18 at 05:18

Snohdo

156
5

Yep! Turns out EOF automatically activates on Ctrl + D. Thanks! – Zevvysan Feb 03 '18 at 05:19
`for (;;) ` -> `while (true)` might be better – Ed Heal Feb 03 '18 at 05:19

How to use Ctrl + D to activate EOF in C++?

2 Answers2