Else increment start Also checkin for X at start position
else { if ( s [ start ] == X ) s [ start ] = Y ; start ++ ; } } String new_s = new String ( s ) ; while ( new_s . length ( ) > 0 && new_s . charAt ( new_s . length ( ) - 1 ) == Z ) { new_s = new_s . substring ( 0 , new_s . length ( ) - 1 ) ; } return new_s ; }