Step 1 — Explicit type

void main() {
  int score = 100;
  String city = 'Dhaka';
  print(score);
  print(city);
}

• Type is written before the variable name.
• Use when you want the type to be obvious.

Step 2 — var (type inferred)

void main() {
  var score = 100;
  var city = 'Dhaka';
  print(score);
  print(city);
}

• Dart infers score as int, city as String.
• Once set, the type does not change.

Step 3 — final (assign once)

void main() {
  final name = 'Alice';
  final age = 25;
  print(name);
  print(age);
}

• Value is set once and cannot be reassigned.
• Use for values that do not change after initialization.

Step 4 — const (compile-time constant)

void main() {
  const pi = 3.14159;
  const appName = 'MyApp';
  print(pi);
  print(appName);
}

• Value must be known at compile time.
• Use for literals and constant expressions.

When to use which

Practice tasks

• Declare a changing counter with var, print it, then change and print again.
• Declare your birth year with final and print it.
• Declare a constant like maxAttempts = 3 with const and print it.