Operators in Dart

What are Operators?

• Operators are symbols that helps you to do some simple calculations and few of them were :

1. Arithmetic Operators
2. Logical Operators
3. Assignment Operators
4. Ternary Operators
5. CasCade Operators
6. TypeCast Operators

Arithmetic Operators

• Used for simple math calculations like addition,subtraction,multiplication,division etc.

Example

void main() {
  int a = 10;
  int b = 5;

  print('Addition: ${a + b}'); // 15
  print('Subtraction: ${a - b}'); // 5
  print('Multiplication: ${a * b}'); // 50
  print('Division: ${a / b}'); // 2.0
  print('Modulus: ${a % b}'); // 0
}

Note: Try this code in DartPad to see the output.

Logical Operators

• Helps to combine multiple boolean expressions and return a boolean result.

1. && operator (AND) - Returns true if both operands are true.
2. || operator (OR) - Returns true if at least one operand is true.
3. ! operator (NOT) - Returns the opposite boolean value of the operand.

Example

void main() {
  bool x = true;
  bool y = false;

  print('AND: ${x && y}'); // false
  print('OR: ${x || y}'); // true
  print('NOT: ${!x}'); // false
}

Note: Try this code in DartPad to see the output.

Assignment Operators

• Used to assign values to variables.

Example

void main() {
  int a = 10; // Assignment
  a += 5; // a = a + 5
  print('a after += : $a'); // 15

  a -= 3; // a = a - 3
  print('a after -= : $a'); // 12

  a *= 2; // a = a * 2
  print('a after *= : $a'); // 24

  a ~/= 4; // a = a / 4
  print('a after ~/= : $a'); // 6
}

Note: Try this code in DartPad to see the output.

Null Aware Assignment Operator

• Used to assign a value to a variable only if that variable is currently null.

  Example

  • Lets say userName is null and we want to assign a default value.

void main() {
  String? userName; // userName is null

  userName ??= 'Guest'; // Assign 'Guest' only if userName is null
  print('User Name: $userName'); // Output: User Name: Guest
}

Ternary Operator

• A shorthand way of writing an if-else statement. if = "?" else = ":" (condition) ? expressionIfTrue : expressionIfFalse

Example

void main() {
  int age = 20;

  String eligibility = (age >= 18) ? 'Eligible to vote' : 'Not eligible to vote';
  print(eligibility); // Output: Eligible to vote
}

Cascade Operator

• Used to perform multiple operations on the same object without rewriting name again and again.

Example

class Person {
  String name = '';
  int age = 0;

  void displayInfo() {
    print('Name: $name, Age: $age');
  }
}
void main() {
  Person person = Person()
    ..name = 'Alice'
    ..age = 30
    ..displayInfo();
}

• If your not familiar with classes, don't worry we will cover it in upcoming sections. Note: Try this code in DartPad to see the output.

Type Cast Operator

• Its either to check the type of an object or to cast an object to a different type.

1. is operator - Used to check if an object is of a specific type.
2. as operator - Used to cast an object to a specific type.

Example

void main() {
  dynamic value = 'Hello, Dart!';

  // Using 'is' operator
  if (value is String) {
    print('Value is a String with length: ${value.length}');
  }

  // Using 'as' operator
  String strValue = value as String;
  print('Casted Value: $strValue');
}

Rescources to Learn Dart

• Courses and Tutorials: Dart And Flutter Series on Youtube ("https://youtube.com/playlist?list=PL9eMLfd38heN2BbPEng6W9qBLl3oJAtwD&si=w_gsoYnIUSzFBLeR")
• Official Dart Documentation: The official Dart website (https://dart.dev) provides comprehensive documentation, tutorials, and guides to help you get started with Dart programming.
• DartPad: An online Dart editor (https://dartpad.dev) that allows you to write, run, and share Dart code directly in your web browser without any setup.
• Flutter Documentation: Since Dart is primarily used with Flutter, the official Flutter documentation (https://flutter.dev/docs) is an excellent resource for learning how to build apps using Dart and Flutter together.

What's Next?

• In the Next Lesson, we will explore Function in Dart. See you there! (Next: Function in Dart )