Compound data types in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are compound data types in Rust?

Compound data types group multiple values into one type. In Rust, common compound types are tuples and arrays.

beginner

How do you define a tuple in Rust?

A tuple is defined by listing values inside parentheses, separated by commas. Example: <code>let t = (10, 20, 30);</code>

beginner

How do you access elements in a tuple?

Use a dot and the index number starting at zero. Example: <code>let x = t.1;</code> gets the second element.

intermediate

What is the difference between arrays and tuples in Rust?

Arrays hold multiple values of the same type and have fixed length. Tuples can hold different types and also have fixed length.

beginner

How do you declare an array of five integers in Rust?

Use square brackets with the type and length. Example: <code>let arr: [i32; 5] = [1, 2, 3, 4, 5];</code>

Which of these is a valid tuple in Rust?

A (10, "hello", true)

B [10, "hello", true]

C {10, "hello", true}

D <10, "hello", true>

Tuples use parentheses and can hold different types, like (10, "hello", true).

How do you access the third element of a tuple named t?

A t.2

B t[2]

C t(2)

D t.3

Tuple elements are accessed with dot and zero-based index, so t.2 is the third element.

What is true about Rust arrays?

A They can hold different types of values.

B They have a fixed size and hold values of the same type.

C They can grow dynamically like vectors.

D They are accessed using dot notation.

Rust arrays have fixed size and all elements must be the same type.

Which syntax correctly declares an array of 3 floats?

A let arr = {1.0, 2.0, 3.0};

B let arr = (1.0, 2.0, 3.0);

C let arr: [f32; 3] = [1.0, 2.0, 3.0];

D let arr: (f32, 3) = [1.0, 2.0, 3.0];

Arrays use square brackets with type and length: [f32; 3].

What happens if you try to access an array element out of bounds in Rust?

A The program compiles but returns zero.

B It returns the last element automatically.

C It silently ignores the access.

D Rust panics at runtime and stops the program.

Rust checks array bounds at runtime and panics if out of bounds to prevent errors.

Explain what compound data types are in Rust and give examples.

Think about how multiple values are grouped in Rust.

Describe how to declare and access elements in a tuple and an array in Rust.

Remember tuples use parentheses and dot notation; arrays use square brackets.