INFO: rewind(stdin) Clears Keyboard Buffer (41159)

SUMMARY

To clear the keyboard buffer in Microsoft C use the function rewind() with the stream STDIN, which is associated with the keyboard by default. The function fflush() clears the buffers that C programs use for stream level I/O. It does not clear the device buffer. The following is an example that shows what happens when the keyboard buffer is not cleared, and then how to clear it:

Sample Code

/* Compile options needed: none
*/ 

#include <stdio.h>

void main(void)
{
   int ch ;

   puts( "Input two or more chars. One is read now." );
   ch = getchar();
   putchar( ch );
   putchar( '\n' );

   puts( "The next char is taken from stdin." );
   ch = getchar( );
   putchar( ch );
   putchar( '\n' );

   rewind( stdin );
   puts( "Input two or more chars. One is read now." );
   ch = getchar();
   putchar( ch );
   putchar( '\n' );

   rewind( stdin );
   puts( "You must enter another char because of the rewind(stdin)" );
   ch = getchar( );
   putchar( ch );
   putchar( '\n' );
}