Language/Expressions/Object_Identity/double_t01.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// @assertion The predefined Dart function identical() is defined such that
/// identical(c1, c2) iff:
/// . . .
///  • c1 and c2 are instances of double and one of the following holds:
///      – c1 and c2 are non-zero and c1 == c2.
///      – Both c1 and c2 are +0.0.
///      – Both c1 and c2 are −0.0.
///      – Both c1 and c2 represent a NaN value with the same underlying bit
///        pattern.
/// @description Checks that two non-zero and non-NaN doubles representing the
/// same value are identical.
/// @author kaigorodov

import "../../../Utils/expect.dart";

mul(var d1, var d2) {
  return d1 * d2;
}

main() {
  var d1 = 32000.5;
  var d2 = 33000.5;
  Expect.isTrue(identical(d1, d1));
  Expect.isTrue(identical(2.5, 2.5));
  Expect.isTrue(identical(2.5, 2.5-0.0));
  Expect.isTrue(identical(2.5, 5.0/2));
  Expect.isTrue(identical(1.5*2, 1.5*2));
  Expect.isTrue(identical(mul(d1, d2), mul(d1, d2)));
  Expect.isTrue(identical(mul(d1, d2), mul(d2, d1)));
}