Primitive Types

Rust has a couple of basic types that are directly implemented into the compiler. In this section, we’ll go through the most important ones.

Further information

Rustlings

primitive_types1: Fill in the rest of the line that has code missing!

 
// primitive_types1.rs
// Fill in the rest of the line that has code missing!
// No hints, there's no tricks, just get used to typing these :)

// I AM NOT DONE

fn main() {
    // Booleans (`bool`)

    let is_morning = true;
    if is_morning {
        println!("Good morning!");
    }

    let // Finish the rest of this line like the example! Or make it be false!
    if is_evening {
        println!("Good evening!");
    }
}

primitive_types2: Fill in the rest of the line that has code missing!

 
// primitive_types2.rs
// Fill in the rest of the line that has code missing!
// No hints, there's no tricks, just get used to typing these :)

// I AM NOT DONE

fn main() {
    // Characters (`char`)

    // Note the _single_ quotes, these are different from the double quotes
    // you've been seeing around.
    let my_first_initial = 'C';
    if my_first_initial.is_alphabetic() {
        println!("Alphabetical!");
    } else if my_first_initial.is_numeric() {
        println!("Numerical!");
    } else {
        println!("Neither alphabetic nor numeric!");
    }

    let // Finish this line like the example! What's your favorite character?
    // Try a letter, try a number, try a special character, try a character
    // from a different language than your own, try an emoji!
    if your_character.is_alphabetic() {
        println!("Alphabetical!");
    } else if your_character.is_numeric() {
        println!("Numerical!");
    } else {
        println!("Neither alphabetic nor numeric!");
    }
}

Hint: single or double quotes, they are different

‘C’ is str, but “C” is &str

primitive_types3: Create an array with at least 100 elements in it where the ??? is.

 
// primitive_types3.rs
// Create an array with at least 100 elements in it where the ??? is.
// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    let a = ???

    if a.len() >= 100 {
        println!("Wow, that's a big array!");
    } else {
        println!("Meh, I eat arrays like that for breakfast.");
    }
}

Hint

There’s a shorthand to initialize Arrays with a certain size that does not require you to type in 100 items (but you certainly can if you want!). For example, you can do: let array = [“Are we there yet?”; 10];

Bonus: what are some other things you could have that would return true for a.len() >= 100?

solution

 
// primitive_types3.rs
// Create an array with at least 100 elements in it where the ??? is.
// Execute `rustlings hint primitive_types3` or use the `hint` watch subcommand for a hint.

fn main() {
    let a = ["a"; 110];

    if a.len() >= 100 {
        println!("Wow, that's a big array!");
    } else {
        println!("Meh, I eat arrays like that for breakfast.");
    }
}

primitive_types4: Get a slice out of Array a 

// primitive_types4.rs
// Get a slice out of Array a where the ??? is so that the test passes.
// Execute `rustlings hint primitive_types4` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    let a = [1, 2, 3, 4, 5];

    let nice_slice = ???

    assert_eq!([2, 3, 4], nice_slice)
}

primitive_types5: Destructure the cat tuple

 
// primitive_types5.rs
// Destructure the `cat` tuple so that the println will work.
// Execute `rustlings hint primitive_types5` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

fn main() {
    let cat = ("Furry McFurson", 3.5);
    let /* your pattern here */ = cat;

    println!("{} is {} years old.", name, age);
}

primitive_types6: Use a tuple index to access the second element of numbers.

 
// primitive_types6.rs
// Use a tuple index to access the second element of `numbers`.
// You can put the expression for the second element where ??? is so that the test passes.
// Execute `rustlings hint primitive_types6` or use the `hint` watch subcommand for a hint.

// I AM NOT DONE

#[test]
fn indexing_tuple() {
    let numbers = (1, 2, 3);
    // Replace below ??? with the tuple indexing syntax.
    let second = ???;

    assert_eq!(2, second,
        "This is not the 2nd number in the tuple!")
}