Scalar data types in Rust - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Rust code with scalar types?

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

Rust

fn main() {
    let x: i32 = 10;
    let y: f64 = 3.5;
    let z: bool = (x as f64) > y;
    println!("{}", z);
}

A false

B true

C 3.5

D Compilation error

💡 Hint

Remember that casting i32 to f64 allows comparison between x and y.

The integer 10 is cast to 10.0 as f64, which is greater than 3.5, so z is true.

❓ Predict Output

intermediate

What value does this Rust code assign to variable `c`?

Given the code below, what is the value of `c` after execution?

Rust

fn main() {
    let a: u8 = 255;
    let b: u8 = 1;
    let c = a.wrapping_add(b);
    println!("{}", c);
}

A 0

B 256

C 1

D Compilation error

💡 Hint

u8 can only hold values from 0 to 255. Wrapping addition wraps around on overflow.

Adding 255 + 1 overflows u8 and wraps to 0 using wrapping_add.

🔧 Debug

advanced

What error does this Rust code produce?

Analyze the code and select the error it will cause when compiled.

Rust

fn main() {
    let x: i32 = 5.0;
    println!("{}", x);
}

A No error, prints 5

B Syntax error

C Runtime panic

D Type mismatch error

💡 Hint

Check the type assigned to x and the value given.

You cannot assign a floating-point value (5.0) to an integer variable (i32) without explicit casting.

📝 Syntax

advanced

Which option correctly declares a character scalar in Rust?

Select the correct Rust code that declares a variable `ch` as a character with value 'R'.

A let ch = 'R';

B let ch: char = "R";

C let ch: char = 'R';

D let ch: character = 'R';

💡 Hint

Characters use single quotes and the type is `char`.

Option C uses the correct type `char` and single quotes for a character literal.

🚀 Application

expert

How many bytes does this Rust scalar type occupy?

In Rust, how many bytes does the scalar type `f64` occupy in memory?

A 8 bytes

B 16 bytes

C Depends on the system architecture

D 4 bytes

💡 Hint

f64 is a 64-bit floating point number.

f64 is a 64-bit (8 bytes) floating point scalar type in Rust, fixed size regardless of architecture.