Why does my C `getline()` function hang after using `cin`?

Using getline() in C : Troubleshooting User Input

When utilizing the getline() method to retrieve user input, it's crucial to be aware of a potential pitfall. Consider the following code:

string messageVar;
cout << "Type your message: ";
getline(cin, messageVar);

Despite attempting to obtain user input, this code hangs indefinitely, never capturing the desired message.

Cause of the Issue:

The issue stems from the fact that the cin >> operator leaves a newline character n in the input buffer. This becomes problematic for getline(), which reads input until encountering a newline. As a result, getline() prematurely terminates without any input being provided.

Solution:

To resolve this problem, you must flush the newline character from the input buffer before calling getline(). This can be achieved using cin.ignore():

string messageVar;
cout << "Type your message: ";
cin.ignore();
getline(cin, messageVar);

By adding cin.ignore(), the newline character left in the buffer is discarded, allowing getline() to function as expected. It will wait for user input and capture the entered message when the Enter key is pressed.

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