void main() {
  // Get the current date and time.
  var now = new DateTime.now();
  print(now);

  // Create a new DateTime with the local time zone.
  var y2k = new DateTime(2000); // January 1, 2000
  print(y2k);

  // Specify the month and day.
  y2k = new DateTime(2000, 1, 2); // January 2, 2...

import 'dart:async';

// fake methods to make the below examples work

Future<int> getFuture() async {
  return 0;
}

void handleValue(int value) {
  print('value is $value');
}

void handleError(int error) {
  print('error is $error');
}

Future dbQuery(String query...

import 'dart:convert' show JSON;

void main() {
  // NOTE: Be sure to use double quotes ("),
  // not single quotes ('), inside the JSON string.
  // This string is JSON, not Dart.
  var jsonString = '''
  [
    {"score": 40},
    {"score": 80}
  ]...

import 'dart:collection';

class Process {
  // Represents a process...
}

class ProcessIterator implements Iterator<Process> {
  @override
  Process current;
  @override
  bool moveNext() {
    return false;
  }
}

// A mythical class that lets you iterate through all
// processes....

import 'dart:math' as math;

void main() {
  trig();
  minmax();
  constants();
  random();
}

void trig() {
  // Cosine
  assert(math.cos(math.PI) == -1.0);

  // Sine
  var degrees = 30;
  var radians = degrees * (math.PI / 180);
  // radians is now 0.52359.
  var sinOf30degrees = math....

void main() {
  assert(int.parse('42') == 42);
  assert(int.parse('0x42') == 66);
  assert(double.parse('0.50') == 0.5);

  assert(num.parse('42') is int);
  assert(num.parse('0x42') is int);
  assert(num.parse('0.50') is double);

  // Specify the ...

// XXX: Now that it's converted to async-await, we really should run this.

import 'dart:async';
import 'dart:html';

String encodeMap(Map data) {
  return data.keys.map((k) {
    return '${Uri.encodeComponent(k)}=' + '${Uri.encodeComponent(data[k])}';
  }).joi...

void main() {
  getAndPutItems();
  checkForItems();
  intersectAndSuperset();
}

void getAndPutItems() {
  var ingredients = new Set();
  ingredients.addAll(['gold', 'titanium', 'xenon']);
  assert(ingredients.length == 3);

  // Adding a duplicate item has no effect.
  i...

import 'dart:io';
import 'dart:convert';
import 'dart:async';

void readFileStreamApi() {
  var config = new File('config.txt');
  Stream<List<int>> inputStream = config.openRead();

  inputStream.transform(UTF8.decoder).transform(new LineSplitter()).li...

void main() {
  //BEGIN
  // Check whether a string contains another string.
  assert('Never odd or even'.contains('odd'));

  // Does a string start with another string?
  assert('Never odd or even'.startsWith('Never'));

  // Does a string end with another string...