Assignment operators in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the basic assignment operator in Rust?

The basic assignment operator in Rust is =. It assigns the value on the right to the variable on the left.

beginner

What does the operator += do in Rust?

The += operator adds the value on the right to the variable on the left and then assigns the result back to the variable.

beginner

How would you use the *= operator in Rust? Give an example.

The <code>*=</code> operator multiplies the variable by the value on the right and assigns the result back. Example: <code>let mut x = 5; x *= 3; // x is now 15</code>

intermediate

Can you chain assignment operators in Rust like x += y += z? Why or why not?

No, Rust does not support chaining assignment operators like x += y += z. Each assignment must be a separate statement because assignment operators return () (unit), not a value.

beginner

List some common compound assignment operators in Rust.

Common compound assignment operators in Rust include: +=, -=, *=, /=, %=, &=, |=, ^=, <<=, >>=.

What does the operator -= do in Rust?

A Divides the left variable by the right value

B Assigns the right value to the left variable without change

C Multiplies the left variable by the right value

D Subtracts the right value from the left variable and assigns the result to the variable

The -= operator subtracts the right value from the left variable and stores the result back in the variable.

Which of these is NOT a valid compound assignment operator in Rust?

A *=

B +=

C ++=

D &=

++= is not a valid operator in Rust. Rust does not have increment (++) operators.

What is the result of this code?<br>let mut a = 10; a /= 2;

A a is 5

B a is 20

C a is 2

D Compilation error

The /= operator divides a by 2 and assigns the result back, so a becomes 5.

Why can't you chain assignment operators like x += y += z in Rust?

A Because Rust does not allow multiple assignments

B Because assignment operators return unit type, not a value

C Because Rust only supports <code>=</code> operator

D Because variables must be immutable

Assignment operators in Rust return the unit type (), so chaining like x += y += z is not allowed.

Which operator would you use to perform a bitwise AND and assign the result to a variable?

A &=

B |=

C ^=

D &&=

The &= operator performs a bitwise AND on the variable and the right value, then assigns the result back.

Explain how compound assignment operators work in Rust and give examples.

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

Why does Rust not allow chaining of assignment operators like x += y += z? What does this tell you about the return type of assignment operators?

Consider what value an assignment expression produces in Rust.