static void swap ( int xp , int yp ) {
  if ( xp == yp ) return ;
  xp = xp + yp ;
  yp = xp - yp ;
  xp = xp - yp ;
}

static void swap ( int xp , int yp ) { if ( xp == yp ) return ; xp = xp + yp ; yp = xp - yp ; xp = xp - yp ; }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier)) (formal_parameter type: (integral_type) name: (identifier))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (return_statement)) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier)))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier)))) (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier))))))