Why Doesn't `getline()` Work After Using `cin`'s Extraction Operator?

Understanding getline() Behavoir

The getline() function in C is used to read characters from the standard input until a newline character is encountered. However, developers may encounter unexpected issues when using getline() after cin's extraction operator (>>).

Problem Description

Users may find that their code is not pausing to receive user input when attempting to capture user-provided messages using getline(). The underlying cause relates to the behavior of the cin extraction operator.

Solution: Flushing the Newline Character

After using cin's extraction operator to read data, it leaves a newline character (n) in the input buffer. When getline() is called immediately after, it stumbles upon this newline character and stops reading immediately.

To resolve this issue, one must flush the newline character from the buffer before invoking getline(). This can be achieved by using cin.ignore() as follows:

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

By inserting cin.ignore(), the newline character is discarded, allowing getline() to read the user's input as intended. This technique ensures that both the cin operator and getline() function smoothly in succession.

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