C++: Using end of file (ctrl+z) to end a loop seems to break cin for the rest of my program

Question

The rest of the program still runs, but none of the cin's prompt the user for input.

double sales;
cout << "(Commision Employee) Please enter the employee's Sales: ";
while (cin >> sales) {
try
{
    employee1.setGrossSales(sales);
}
catch (invalid_argument& e)
{
    cout << "\nException: " << e.what() << "\n\n";
}
cout << "Please re-enter value if an error occured, otherwise enter end-of-file (ctrl+z): ";
}

string ssn;
cout << "(Base Plus Commision Employee) Please enter the SSN with dashes: ";
cin >> ssn;
employee2.setSocialSecurityNumber(ssn);

The cin following the loop doesn't function like I expected it too. What I gather is that cin has a boolean end-of-file marker that is switched to true upon receiving the end-of-file (ctrl+z on windows). It's this marker that prevents cin from operating again. I have found that I can use std::cin.clear(); to clear this marker.

I found this answer here which does a better job at both describing the same issue I had and answering it: while (cin >> x) and end-of-file issues

For my purposes, this was all I needed.

Why would you expect `cin` to keep working after you told it the file had ended? — Galik, Apr 23 '18 at 22:36
Post a [MCVE], not a fragment. What platform? Visual C++ maybe? — Jive Dadson, Apr 23 '18 at 22:43
You already have a good exit. If the user types in anything that isn't a double, you're out of the loop. Smarten that up a bit to clear the error flag, read the input as a string, test the string for "exit" and either exit or chuck the string and go back to looking for `double`s and you're good to go. — user4581301, Apr 23 '18 at 23:15
@JiveDadson, I have added 4 lines to my code in the question. The cin >> ssn; doesn't prompt the user for input. — poptonite, Apr 24 '18 at 03:54
Possible duplicate of [while (cin >> x) and end-of-file issues](https://stackoverflow.com/questions/1078218/while-cin-x-and-end-of-file-issues) — Toby Speight, Apr 24 '18 at 11:00

score 1 · Answer 1 · answered Apr 23 '18 at 22:52

1

ctrl+z is actually 0x1A byte that sets the std::basic_ios::eof to true, which means that associated stream has reached end-of-file.

Windows system can not read beyond the 0x1A (EOF) character but Unix can.

answered Apr 23 '18 at 22:52

Abhishek Keshri

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C++: Using end of file (ctrl+z) to end a loop seems to break cin for the rest of my program

1 Answers1