Character type in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Rust char type used for?

The char type in Rust represents a single Unicode scalar value, which means it can hold any valid Unicode character, including letters, numbers, emojis, and symbols.

beginner

How many bytes does a Rust char use in memory?

A Rust char uses 4 bytes (32 bits) in memory to store a Unicode scalar value.

beginner

How do you write a character literal in Rust?

You write a character literal using single quotes, like 'a', '😊', or '\n' for newline.

beginner

Can a Rust char hold multiple characters or strings?

No, a Rust char holds exactly one Unicode scalar value, which is one character. For multiple characters, use a String or string slice &str.

intermediate

How can you convert a char to its numeric Unicode code point in Rust?

You can convert a <code>char</code> to a <code>u32</code> number using the <code>as</code> keyword, like <code>let code = 'A' as u32;</code>.

What is the size in bytes of a Rust char?

A 8 bytes

B 1 byte

C 4 bytes

D 2 bytes

A Rust char always uses 4 bytes to store a Unicode scalar value.

Which of these is a valid Rust character literal?

A "a"

B 'ab'

C "ab"

D 'a'

Rust character literals use single quotes and hold exactly one character, like 'a'.

What does the Rust char type represent?

A A single Unicode scalar value

B A byte of data

C A string of characters

D An integer number

The char type represents a single Unicode scalar value, which can be any valid Unicode character.

How do you convert a char to its Unicode code point number?

A Using <code>char as u32</code>

B Using <code>char.to_u32()</code>

C Using <code>char.to_string()</code>

D Using <code>char.to_int()</code>

You convert a char to a number with char as u32.

Can a Rust char hold an emoji character?

A No, only ASCII characters are allowed

B Yes, because emojis are Unicode scalar values

C Only if converted to a string first

D Only if stored as bytes

Rust char can hold any Unicode scalar value, including emojis.

Explain what the Rust char type is and how it differs from a string.

Think about the difference between a single letter and a word.

Describe how to write and use a character literal in Rust.

Remember how characters are shown in code.