Assignment operators in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the assignment operator (=) in C++?

The assignment operator (=) is used to copy the value from the right side to the variable on the left side.

beginner

Explain the combined assignment operator += with an example.

The operator += adds the right side value to the left side variable and assigns the result back to the left variable.<br>Example: int x = 5; x += 3; // x becomes 8

beginner

List three compound assignment operators in C++ besides +=.

Three compound assignment operators are:<br>- -= (subtract and assign)<br>- *= (multiply and assign)<br>- /= (divide and assign)

intermediate

What happens if you write a = b = c; in C++?

This is called chained assignment. It assigns the value of c to b, then assigns b's value to a. Both a and b end up with the value of c.

intermediate

Why should you be careful when using the assignment operator inside conditions?

Using assignment (=) inside conditions can cause bugs because it assigns a value instead of comparing. For comparison, use ==. For example, if (x = 5) assigns 5 to x and always evaluates true, which is usually unintended.

What does the operator *= do in C++?

A Divides the left variable by the right and assigns the result

B Subtracts the right value from the left variable

C Adds the right value to the left variable

D Multiplies the left variable by the right and assigns the result

The operator *= multiplies the left variable by the right value and stores the result back in the left variable.

What is the result of this code?<br>int a = 2; a += 3;

A a is 5

B a is 6

C a is 3

D a is 2

The operator += adds 3 to a's current value 2, so a becomes 5.

Which operator is used to assign a value to a variable?

A =

B +=

C ==

D !=

The single equals sign (=) is the assignment operator in C++.

What does this code do?<br>int x = 1, y = 2; x = y = 5;

A Only x becomes 5

B x and y both become 5

C Only y becomes 5

D x becomes 2, y becomes 5

The assignment is chained: y is assigned 5, then x is assigned y's value, so both become 5.

Why is this condition problematic?<br>if (a = 10)

A It compares a to 10

B It checks if a is not equal to 10

C It assigns 10 to a and always evaluates true

D It causes a syntax error

Using = assigns 10 to a, so the condition is always true, which is usually a mistake.

Explain how compound assignment operators work and give two examples.

Think about how they combine an operation and assignment in one step.

Describe what happens in chained assignments and why it might be useful.

Consider how values flow from right to left.