blob: 58b4d16e2b9667e6a70f390453c685ad7881f00a [file] [log] [blame]
 // Copyright (c) 2012, 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. // Test that a coin toss with Random.nextBool() is fair. import "package:expect/expect.dart"; import 'dart:math'; main() { var seed = new Random().nextInt(1 << 16); print("coin_test seed: \$seed"); var rnd = new Random(seed); var heads = 0; var tails = 0; for (var i = 0; i < 10000; i++) { if (rnd.nextBool()) { heads++; } else { tails++; } } print("Heads: \$heads\n" "Tails: \$tails\n" "Ratio: \${heads / tails}\n"); Expect.approxEquals(1.0, heads / tails, 0.1); heads = 0; tails = 0; for (var i = 0; i < 10000; i++) { rnd = new Random(i); if (rnd.nextBool()) { heads++; } else { tails++; } } print("Heads: \$heads\n" "Tails: \$tails\n" "Ratio: \${heads / tails}\n"); Expect.approxEquals(1.0, heads / tails, 0.1); // A sequence of newly allocated Random number generators should have fair // initial tosses. heads = 0; tails = 0; for (var i = 0; i < 10000; i++) { rnd = new Random(); if (rnd.nextBool()) { heads++; } else { tails++; } } print("Heads: \$heads\n" "Tails: \$tails\n" "Ratio: \${heads / tails}\n"); Expect.approxEquals(1.0, heads / tails, 0.1); }