Assignment Shortcuts

Part of the Fundamentals section of Coddy's Dart journey — lesson 20 of 94.

In Dart, assignment shortcuts combine arithmetic operators with assignment to modify variables concisely.

1. Addition Assignment (+=)

void main() {
  int score = 10;
  score += 5;  // Equivalent to: score = score + 5;
  print('Score after adding 5: $score');
}

2. Subtraction Assignment (-=)

void main() {
  int lives = 3;
  lives -= 1;  // Equivalent to: lives = lives - 1;
  print('Lives after losing 1: $lives');
}

3. Multiplication Assignment (*=)

void main() {
  int points = 5;
  points *= 2;  // Equivalent to: points = points * 2;
  print('Points after doubling: $points');
}

4. Division Assignment (/=)

void main() {
  double price = 100.0;
  price /= 2;  // Equivalent to: price = price / 2;
  print('Price after 50% discount: $price');
}

Challenge

Easy

Create a program that tracks a player's game statistics using assignment shortcuts:

Declare an integer variable score with an initial value of 100
Declare an integer variable bonus with an initial value of 50
Declare a integer variable multiplier with an initial value of 2
Declare an integer variable penalty with an initial value of 30
Print the initial score with the message: Initial score: 100
Use the += operator to add the bonus to the score
Print the score after adding the bonus: Score after bonus: 150
Use the *= operator to multiply the score by the multiplier
Print the score after applying the multiplier: Score after multiplier: 300
Use the -= operator to subtract the penalty from the score
Print the final score: Final score: 270

Your output must match the exact format shown above.

Cheat sheet

Assignment shortcuts combine arithmetic operators with assignment to modify variables concisely:

Addition Assignment (+=)

score += 5;  // Equivalent to: score = score + 5;

Subtraction Assignment (-=)

lives -= 1;  // Equivalent to: lives = lives - 1;

Multiplication Assignment (*=)

points *= 2;  // Equivalent to: points = points * 2;

Division Assignment (/=)

price /= 2;  // Equivalent to: price = price / 2;

Try it yourself

void main() {
  // Declare your variables here
  int score = ?;
  int bonus = ?;
  int multiplier = ?;
  int penalty = ?;
  
  // Print initial score
  print("Initial score: $score");
  
  // Add bonus using += operator
  score ? bonus;
  
  // Print score after bonus
  print("Score after bonus: $score");
  
  // Apply multiplier using *= operator
  score ? multiplier;
  
  // Print score after multiplier
  print("Score after multiplier: $score");
  
  // Subtract penalty using -= operator
  score ? penalty;
  
  // Print final score
  print("Final score: $score");
}