SOMEBODY can give me a hint !!!

Question

If we have the input string "i am waiting for you."
and if we want to follow the following rule ie: for->4 ait->8 you->u
the input string should be changed to "i am w8ing 4 u."
(You are not allowed to use subString method)
somebody can tell me how to do it?
i am a little bit confusing.
THANKS!

Answer 1

  char[] buf    = new char[3];
  StringBuffer out = new StringBuffer();
    // prefill the buffer
  buf[0] = yourString.charAt(0);
  buf[1] = yourString.charAt(1);
  for ( int x = 2; x < record.length; x++ )
      // get the next character
    buf[2] = record[x];
      // do we have a string (in buffer) to replace ?
    boolean match = true;
    String test = new String( buf );
    if      ( test.equals( "for" ) )  buf[0] = '4';
    else if ( test.equals( "ait" ) )  buf[0] = '8';
    else if ( test.equals( "you" ) )  buf[0] = 'u';
    else match = false;
      // output the first character in buffer
    out.append( buf[0] );
      // if matched, then discard last two buffers
    if ( match )
      buf[1] = yourString.charAt( ++x );
      buf[2] = yourString.charAt( ++x );
      // now shuffle the buffer by one character
    buf[0] = buf[1];
    buf[1] = buf[2];
    // don't forget the last two characters in buf !
  out.append( buf[1] );
  out.append( buf[2] );The above code isn't totally correct - treat it as pseudo code and you should see the algorithm I'm suggesting.