Jaime Wren
e160f89499
Change-Id: Idea1235650b94fc77455cd46297803d3a169a791 Reviewed-on: https://dart-review.googlesource.com/3708 Commit-Queue: Jaime Wren <jwren@google.com> Reviewed-by: Janice Collins <jcollins@google.com>
63 lines
1.5 KiB
Dart
63 lines
1.5 KiB
Dart
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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// Test that a coin toss with Random.nextBool() is fair.
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// Library tag to allow Dartium to run the test.
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library coin_test;
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import "package:expect/expect.dart";
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import 'dart:math';
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main() {
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var seed = new Random().nextInt(1 << 16);
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print("coin_test seed: $seed");
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var rnd = new Random(seed);
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var heads = 0;
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var tails = 0;
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for (var i = 0; i < 10000; i++) {
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if (rnd.nextBool()) {
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heads++;
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} else {
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tails++;
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}
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}
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print("Heads: $heads\n"
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"Tails: $tails\n"
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"Ratio: ${heads/tails}\n");
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Expect.approxEquals(1.0, heads / tails, 0.1);
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heads = 0;
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tails = 0;
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for (var i = 0; i < 10000; i++) {
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rnd = new Random(i);
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if (rnd.nextBool()) {
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heads++;
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} else {
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tails++;
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}
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}
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print("Heads: $heads\n"
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"Tails: $tails\n"
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"Ratio: ${heads/tails}\n");
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Expect.approxEquals(1.0, heads / tails, 0.1);
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// A sequence of newly allocated Random number generators should have fair
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// initial tosses.
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heads = 0;
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tails = 0;
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for (var i = 0; i < 10000; i++) {
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rnd = new Random();
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if (rnd.nextBool()) {
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heads++;
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} else {
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tails++;
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}
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}
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print("Heads: $heads\n"
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"Tails: $tails\n"
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"Ratio: ${heads/tails}\n");
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Expect.approxEquals(1.0, heads / tails, 0.1);
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}
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