Rust by Example

// `let` can be used to bind the members of a tuple to variables

let (integer, boolean) = pair;

(boolean, integer)

}

// The following struct is for the activity.

#[derive(Debug)]

struct Matrix(f32, f32, f32, f32);

fn main() {

// A tuple with a bunch of different types

let long_tuple = (1u8, 2u16, 3u32, 4u64,

-1i8, -2i16, -3i32, -4i64,

0.1f32, 0.2f64,

'a', true);

// Values can be extracted from the tuple using tuple indexing

println!("long tuple first value: {}", long_tuple.0);

println!("long tuple second value: {}", long_tuple.1);

// Tuples can be tuple members

let tuple_of_tuples = ((1u8, 2u16, 2u32), (4u64, -1i8), -2i16);

// Tuples are printable

println!("tuple of tuples: {:?}", tuple_of_tuples);

// But long Tuples cannot be printed

// let too_long_tuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13);

// println!("too long tuple: {:?}", too_long_tuple);

// TODO ^ Uncomment the above 2 lines to see the compiler error

let pair = (1, true);

println!("pair is {:?}", pair);

println!("the reversed pair is {:?}", reverse(pair));

// To create one element tuples, the comma is required to tell them apart

// from a literal surrounded by parentheses

println!("one element tuple: {:?}", (5u32,));

println!("just an integer: {:?}", (5u32));

//tuples can be destructured to create bindings

let tuple = (1, "hello", 4.5, true);

let (a, b, c, d) = tuple;

println!("{:?}, {:?}, {:?}, {:?}", a, b, c, d);

let matrix = Matrix(1.1, 1.2, 2.1, 2.2);

println!("{:?}", matrix);

}

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Activity

   1. Recap: Add the fmt::Display trait to the Matrix struct in the above example, so that if you switch from printing the debug format {:?} to the display format {}, you see the following output:

( 1.1 1.2 )

( 2.1 2.2 )

You may want to refer back to the example for print display.

   2. Add a transpose function using the reverse function as a template, which accepts a matrix as an argument, and returns a matrix in which two elements have been swapped. For example:

println!("Matrix:\n{}", matrix);

println!("Transpose:\n{}", transpose(matrix));

results in the output:

Matrix:

( 1.1 1.2 )

( 2.1 2.2 )

Transpose:

( 1.1 2.1 )

( 1.2 2.2 )

Arrays and Slices

An array is a collection of objects of the same type T, stored in contiguous memory. Arrays are created using brackets [], and their length, which is known at compile time, is part of their type signature [T; length].