INFO: rewind(stdin) Clears Keyboard Buffer

• The C Run-time (CRT) included with: - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, 6.0ax - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, 1.52 - Microsoft Visual C++, 32-bit Edition, versions 1.0, 2.0, 2.1, 4.0, 5.0

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.

MORE INFORMATION

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' );
   }