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DAY 10
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Mobile Development

Dart & Flutter - 學寫App | 菜鳥筆記 | 堅持30天挑戰系列 第 10

Dart 語言 | 基本練習(上)

Dart Exercise

01-Fundamentals

playground.dart

Code

main() {
  var firstName = 'Mahmud';
  String lastName = 'Ahsan';

  print(firstName + ' ' + lastName);
}

Output

Mahmud Ahsan

playground2.dart

Code

main() {
  stdout.writeln('What is your name: ?');
  String name = stdin.readLineSync();
  print('My nae is $name');
}

Output

What is your name: ?
aa
My nae is aa

02-Data Types

playground3.dart

Code

main() {
  int amount1 = 100;
  var amount2 = 200;

  print('Amount1: $amount1 | Amount2: $amount2 \n');

  double dAmount1 = 100.11;
  var dAmount2 = 200.22;

  print('dAmount1: $dAmount1 | dAmount2: $dAmount2 \n');

  String name1 = 'Mahmud';
  var name2 = 'Ahsan';

  print('My name is: $name1 $name2 \n');

  bool isItTrue1 = true;
  var isItTrue2 = false;

  print('isItTrue1: $isItTrue1 | isItTrue2: $isItTrue2 \n');

  dynamic weakVariable = 100;
  print('WeakVariable 1: $weakVariable \n');

  weakVariable = 'Dart Programming';
  print('WeakVariable 2: $weakVariable');
}

Output

Amount1: 100 | Amount2: 200

dAmount1: 100.11 | dAmount2: 200.22

My name is: Mahmud Ahsan

isItTrue1: true | isItTrue2: false

WeakVariable 1: 100

WeakVariable 2: Dart Programming

03-String, Type Conversion, Constant, Null

playground4.dart

Code

main() {
  var s1 = 'Single quotes work well for string literals.';
  var s2 = 'Double quotes work just as well.';
  var s3 = 'It\'s easy  to escape the string delimiter.';
  var s4 = "It's even easier to use the other delimiter.";

  print(s1);
  print(s2);
  print(s3);
  print(s4);
  print('');

  //RAW String
  var s = r'In a raw string, not even \n gets special treatment.';
  print(s);
}

Output

Single quotes work well for string literals.
Double quotes work just as well.
It's easy  to escape the string delimiter.
It's even easier to use the other delimiter.

In a raw string, not even \n gets special treatment.

playground5.dart

Code

main() {
  var age = 35;
  var str = 'My age is : $age';
  print(str);
}

Output

My age is : 35

playground6.dart

Code

main() {
  var s1 = '''You can create multi-line strings like this one.
  ''';
  var s2 = """This is also a multi-line string.""";

  print(s1);

  print(s2);
}

Output

You can create multi-line strings like this one.

This is also a multi-line string.

playground7.dart

Code

main() {
  // String -> int
  var one = int.parse('1');
  assert(one == 1);

  // String -> double
  var onePointOne = double.parse('1.1');
  assert(onePointOne == 1.1);

  // int -> String
  String oneAsString = 1.toString();
  assert(oneAsString == '1');

  // double -> String
  String piAsString = 3.14159.toStringAsFixed(2);
  assert(piAsString == '3.14');
}

playground8.dart

Code

main() {
  const aConstNum = 0; // int constant
  const aConstBool = true; // bool constant
  const aConstString = 'a constant string'; // string constant

  print(aConstNum);
  print(aConstBool);
  print(aConstString);

  print(aConstNum.runtimeType);
  print(aConstBool.runtimeType);
  print(aConstString.runtimeType);
}

Output

0
true
a constant string
int
bool
String

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Flutter 常用組件講解 | ListViewWidget | 動態清單
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Dart語言 | 基本練習 (中)
系列文
Dart & Flutter - 學寫App | 菜鳥筆記 | 堅持30天挑戰12

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