Integer types in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are the two main categories of integer types in Rust?

Signed integers (can be positive or negative) and unsigned integers (only positive and zero).

beginner

What does i32 mean in Rust?

i32 is a signed 32-bit integer type. It can store values from -2,147,483,648 to 2,147,483,647.

beginner

What is the difference between u8 and i8 in Rust?

u8 is an unsigned 8-bit integer (0 to 255), while i8 is a signed 8-bit integer (-128 to 127).

intermediate

Why would you choose an unsigned integer type in Rust?

Use unsigned integers when you know the value will never be negative, which allows storing a larger positive range.

intermediate

What happens if you try to store a number outside the range of an integer type in Rust?

Rust will cause a compile-time error or panic in debug mode due to overflow or underflow, helping catch bugs early.

Which Rust integer type can store the value -100?

A i32

B u32

C u8

D usize

i32 is signed and can store negative numbers like -100. Unsigned types like u32 and u8 cannot.

What is the range of values for u16 in Rust?

A -128 to 127

B -32,768 to 32,767

C 0 to 65,535

D 0 to 255

u16 is an unsigned 16-bit integer, so it stores values from 0 to 65,535.

Which integer type is best for counting items that can never be negative?

A i64

B u64

C i8

D isize

u64 is unsigned and can only hold zero or positive numbers, perfect for counting.

What does isize represent in Rust?

A A floating-point number

B An unsigned 32-bit integer

C A fixed 64-bit unsigned integer

D A signed integer with size depending on the computer architecture

isize is a signed integer whose size depends on the system (32-bit or 64-bit).

What will happen if you add 1 to the maximum value of u8 in debug mode?

A It causes a panic (runtime error)

B It becomes a negative number

C It wraps around to 0 without error

D It converts to a larger integer type automatically

In debug mode, Rust checks for overflow and will panic if it happens, helping catch bugs.

Explain the difference between signed and unsigned integer types in Rust.

Think about whether the number can be negative or not.

Describe what happens when integer overflow occurs in Rust during debug mode.

Consider how Rust protects you from mistakes with numbers.