static void insert_at_bottom ( char x ) {
  if ( st . isEmpty ( ) ) st . push ( x ) ;
  else {
    char a = st . peek ( ) ;
    st . pop ( ) ;
    insert_at_bottom ( x ) ;
    st . push ( a ) ;
  }
}

static void insert_at_bottom ( char x ) { if ( st . isEmpty ( ) ) st . push ( x ) ; else { char a = st . peek ( ) ; st . pop ( ) ; insert_at_bottom ( x ) ; st . push ( a ) ; } }
(method_declaration (modifiers) type: (void_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (if_statement condition: (parenthesized_expression (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) consequence: (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier)))) alternative: (block (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (method_invocation object: (identifier) name: (identifier) arguments: (argument_list)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list))) (expression_statement (method_invocation name: (identifier) arguments: (argument_list (identifier)))) (expression_statement (method_invocation object: (identifier) name: (identifier) arguments: (argument_list (identifier))))))))