Clear the cin buffer before another input request, c++

Question

I have the following code:

int choice = 0;
char st1[N];

cout << "enter choice" <<endl;
cin >> choice;

cout << "enter sentence" << endl;
cin.get(st1, N-1);

when getting to cin.get line, no matter what the input is, it will read \\0 char into st1[0] and that's it.

I assume it has something to do with the latest cin ( into choice variable ).

How do i "clean" cin buffer before getting new input from the user? if that's possible.

thanks

Answer 1

You might use ignore to drop the newline from the buffer (eg drop X characters before the newline as delimiter). Extraction and ignore stop when the delimiter is extracted.

eg

cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

Also related: Why would we call cin.clear() and cin.ignore() after reading input?

Answer 2

您总是可以尝试使用cin.sync() 。

Answer 3

Do a getchar() after cin >> choice; . This will consume the \\n from the input buffer.

Since choice is of type int , the \\n is left over in the buffer and when the string input is taken, this \\n is encountered and it stops taking input there.