static boolean isTriangular ( int num ) {
  if ( num < 0 ) return false ;
  int sum = 0 ;
  for ( int n = 1 ;
  sum <= num ;
  n ++ ) {
    sum = sum + n ;
    if ( sum == num ) return true ;
  }
  return false ;
}

static boolean isTriangular ( int num ) { if ( num < 0 ) return false ; int sum = 0 ; for ( int n = 1 ; sum <= num ; n ++ ) { sum = sum + n ; if ( sum == num ) return true ; } return false ; }
(method_declaration (modifiers) type: (boolean_type) name: (identifier) parameters: (formal_parameters (formal_parameter type: (integral_type) name: (identifier))) body: (block (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (decimal_integer_literal))) consequence: (return_statement (false))) (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) (for_statement init: (local_variable_declaration type: (integral_type) declarator: (variable_declarator name: (identifier) value: (decimal_integer_literal))) condition: (binary_expression left: (identifier) right: (identifier)) update: (update_expression (identifier)) body: (block (expression_statement (assignment_expression left: (identifier) right: (binary_expression left: (identifier) right: (identifier)))) (if_statement condition: (parenthesized_expression (binary_expression left: (identifier) right: (identifier))) consequence: (return_statement (true))))) (return_statement (false))))