C getchar vs scanf

Question

I am confused by a piece of code found in a function I am studying:

char GetCommand( void )
{
    char command;

    do {
        printf( \"Enter command (q=         


        

Answer 1

getchar reads one character from standard input. If you put it in a while loop, it will continue to read one character at a time until the condition is false.

What the Flush function is doing is reading until it encounters a newline (\n). This is the character produced when the user hits the enter key.

So, the code you gave will read one character (I'm unclear on why it uses scanf for this instead of simply getchar, which would be faster), and then discards the rest of the input until the user hits enter.

If you were to feed this program foobar, it would take the f and discard the oobar in the Flush function. Without calling flush, the f could go to one scanf, and the second scanf would get the first o.