# include <stdio.h>

int main ( )
{
  int i;

  printf ( "\n" );
  printf ( "The UNIX > operator can redirect output send to standard output.\n" );
  printf ( "But messages send to standard error ALWAYS appear on the screen.\n" );
  printf ( "\n" );

  printf ( "This message is sent ( by default ) to standard output.\n" );
  fprintf ( stdout, "This message is sent explicitly to standard output.\n" );
  fprintf ( stderr, "This message is sent explicitly to standard error.\n" );

  for ( i = 0; i <= 10; i++ )
  {
    printf ( "%d  %d\n", i, i * i );
  }

  fprintf ( stderr, "I printed a table of squares from 1 to 10.\n" );

  return 0;
}