Assignment Operators

Assignment operators are used to assign values to variables. Dart supports a variety of compound assignment operators that perform an operation and assign the result in a single step.

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List of Assignment Operators

Operator	Description	Equivalent Expression
=	Simple assignment	x = y
+=	Add and assign	x = x + y
-=	Subtract and assign	x = x - y
*=	Multiply and assign	x = x * y
/=	Divide and assign	x = x / y
~/=	Integer divide and assign	x = x ~/ y
%=	Modulo and assign	x = x % y
??=	Null-aware assignment	x = x ?? y (Assigns only if x is null)

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Code Examples

Compound Assignments

dart
void main() {
  double price = 100.0;
  price += 10; // Equivalent to: price = price + 10;
  print(price); // 110.0

  price *= 0.9; // Apply 10% discount
  print(price); // 99.0
}

Null-Aware Assignment (??=)

The ??= operator assigns a value to a variable only if the variable is currently null.

dart
void main() {
  String? username;

  username ??= "Guest";
  print(username); // Guest

  username ??= "Admin"; // Will not overwrite since username is not null
  print(username); // Guest
}

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Summary

• Compound assignment operators make code cleaner and more readable.
• The ??= operator is extremely useful for setting default fallback values for nullable variables.