Complete Program

Here is the complete program. Legal characters for this program are all printable characters, and selected whitespace (tab, newline, and carriage return.) This allows in some characters that are not in legal C, but might be in comments.

#include <stdio.h>

void putBad( char *msg )
{
  int j;
  for ( j=0; msg[j]; j++ )
    putchar( msg[j] );
}

void main( void )
{
  int ch;

  while ( (ch = getchar()) != EOF )
  {
    if ( isprint( ch ) || ch == '\t' || ch == '\n' || ch == '\r' )
    {
      putchar( ch );
    }
    else
    {
      putBad( "/* BAD */");
    }
  }
}