The standard input stream is a pointer to a complex FILE structure named stdin. This stream reads any characters typed from the keyboard to be formatted by the scanf() function.
Like the output stream, by default, the input stream is also buffered. For input, this means that characters are sent to the buffer. The buffer is not flushed until either the buffer is full or until CR is encountered in the input stream. As we enter characters, program control is maintained by the console and is not returned to our program until the buffer is flushed. The processing of the input characters then appears to our program as if they were received one at a time.
In reality, however, it is a bit more complicated than this. The console has two modes of processing—cooked mode and raw mode.
Cooked mode uses buffered input and is the default mode unless it is explicitly changed. It also means that we can alter our input in the...