20.1.2 Console I/O
Return true if a keypress is waiting to be read.
Read a keypress and return the resulting character. Nothing is
echoed to the console. This call will block if a keypress is not
already available, but will not wait for Enter to be pressed.
If the pressed key was a special function key, this will return
'\xe0'; the next call will return the
keycode. The Control-C keypress cannot be read with this
Similar to getch(), but the keypress will be echoed if it
represents a printable character.
Print the character char to the console without buffering.
Cause the character char to be ``pushed back'' into the
console buffer; it will be the next character read by
getch() or getche().
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