Character type in Rust - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Rust code using char?

Consider the following Rust code snippet. What will it print?

Rust

fn main() {
    let c: char = 'A';
    let n = c as u8 + 1;
    println!("{}", n as char);
}

A C

B B

C A

D Error: cannot cast char to u8 directly

💡 Hint

Remember that chars can be cast to their ASCII numeric values.

The character 'A' has ASCII value 65. Adding 1 gives 66, which corresponds to 'B'.

❓ Predict Output

intermediate

What does this Rust code print with Unicode char?

Look at this Rust code. What will it output?

Rust

fn main() {
    let heart = '\u{2764}';
    println!("{}", heart);
}

A ❤

B \u{2764}

C Error: invalid Unicode escape

D ?

💡 Hint

Unicode escapes represent characters by their code points.

The Unicode code point U+2764 is the heart symbol ❤, so it prints that.

🔧 Debug

advanced

Why does this Rust code fail to compile?

This Rust code tries to convert a string to a char but fails. Why?

Rust

fn main() {
    let s = "hello";
    let c: char = s;
    println!("{}", c);
}

A Missing semicolon after let c: char = s

B String "hello" is too long to convert to char

C Cannot assign &str to char directly; types mismatch

D char type cannot be printed with println!

💡 Hint

Check the types of s and c carefully.

A &str (string slice) cannot be assigned directly to a char because they are different types.

📝 Syntax

advanced

Which option correctly declares a char in Rust?

Choose the correct Rust syntax to declare a char variable holding the letter 'z'.

A let c: char = "z";

B let c: char = z;

C let c = 'z';

D let c: char = 'z';

💡 Hint

Chars use single quotes in Rust.

Chars are declared with single quotes and explicit type annotation is correct here.

🚀 Application

expert

How many Unicode scalar values are in this Rust char array?

Given this Rust code, how many Unicode scalar values does the array contain?

Rust

fn main() {
    let chars: [char; 4] = ['a', 'é', '𝄞', '\n'];
    println!("{}", chars.len());
}

A 4

B 3

C 5

D Error: invalid char literal

💡 Hint

Each char in Rust represents one Unicode scalar value regardless of byte length.

The array has exactly 4 chars: 'a', 'é', '𝄞' (a musical symbol), and newline '\n'.