Question

I know how to do this in C but have no idea for a C++ solution. I want the following to be fail safe, but after providing a string or even a char to the input, the program hangs. How to read input stream including \n to free it?

int main() {
    int num;
    do { 
        std::cin.clear();
        std::cin >> num;
        while ( std::cin.get() != '\n' );
    } while ( !std::cin.good() || num > 5 );
    return 0;
}

Answer 1

Once the stream is in an error state all read operations will fail. This means that, if the cin >> num read fails, the loop with the get() calls will never end: all those get()s will fail. Skipping to the end of the line can only be done after clearing the error state.