Assignment operators

Learn shortcut assignments with =, +=, -=, *=, /= and ++/--.

Assignment operators

The = operator assigns the right value to the left variable: x = 5;. This is the basic assignment operator.

C++ also offers compound assignment operators: +=, -=, *=, /=, %=. They perform an operation and an assignment in one step.

For example, x += 5 means the same as x = x + 5. Similarly x -= 3 = x = x - 3, x *= 2 = x = x * 2. These operators make code shorter and more readable.

Using compound assignment

Compound assignment operators are handy for updating a variable. To increment a counter each step, write count += 1; this is the same as count = count + 1.

Example: starting with score = 50. score += 20 → 70. score -= 10 → 60. The final score is 60.

These operators are not limited to numbers; += works with std::string for concatenation: text += "!". But multiplication and division apply only to numbers.

Exercise Update with compound assignment

Inside main, declare int score = 50;. Update score with score += 20; and score -= 10;. Then print score with std::cout using std::endl. The output must be 60.

Show example solution

#include <iostream>

int main() {
    // Declare score and update it with +=, -=
    int score = 50;
    score += 20;
    score -= 10;
    // Print with std::cout
    std::cout << score << std::endl;
    return 0;
}

Test yourself

Match assignment operators

=

Basic assignment
+=

Add and assign
-=

Subtract and assign
*=

Multiply and assign
What is x += 5 shorthand for?
- x = 5
- x = x + 5
- x + 5
- x == 5
Show answer

x = x + 5 — x += 5 is shorthand for x = x + 5.
Subtract and assign
```
score ____ 10;
```
Show answer
```
score -= 10;
```

Next lesson: Comparison operators

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