Week 05 Weekly Exercises

For example, we would write a struct that would store two `i32` values, and then we would write a function that would take two `i32` values and return an `i32` value (maybe doing some sort of addition).

This is fine for simple programs, but what if we wanted to write a function that would take two `\text{f32}` values, perform some operation, and then return an `f32` value? We would have to write a new function for that. What if we wanted to write a function that would take two `\text{String}` values, perform the same operation, and then return a `\text{String}` value? We would have to write a new function for that, even though the only thing that changed were the types inputted and outputted to the function!

Suddenly, we have multiple functions that all do the same thing - resulting in a lot of duplicated code, more code to maintain, test and write! There are many ways we could make writing this code easier; we can use generics to solve this problem!

• First - implement a generic function called first that takes a slice of some type `T`, and returns a shared borrow of first value in the slice. Be sure to use the provided doctests to help you write your function.
• Second - modify the given Point struct to be generic. It should be able to store two values of one type T. Be sure to use the provided doctests to help you write your struct.
• Third - modify the existing method on the Point struct called distance that takes a second Point and returns the distance between the two points. Modify this method to be only be implemented for Point instances where the type of the x and y values are f32
• Finally - create a generic method on the Point struct called new that creates a new Point. This method should take two values of type `T` and return a new Point instance with the given values.

  Ideally, your method should return Self, and construct a Self.

When you think your program is working, you can use autotest to run some simple automated tests:

6991 autotest

When you are finished working on this exercise, you must submit your work by running give:

6991 give-crate

The recommended due date for this exercise is Week 7 Wednesday 21:00:00.

You must run give before Week 10 Friday 17:00:00 to obtain the marks for this exercise. Note that this is an individual exercise; the work you submit with give must be entirely your own.

The provided code will handle all of the input parsing using the awesome rustyline crate. You will be modifying the code in die.rs

In this exercise, you will need to complete the following tasks, by modifying the code in die.rs ONLY.

1. Create a Trait with a single function , that describes the behaviour of getting the value of a roll of a dice/coin.
2. Implement the trait for Coin (a coin "roll" will either be `1` or `2`).
3. Implement the trait for Dice (each dice will be a number between 1 and the number of sides on the dice (inclusive) - a D4 for example, has 4 sides).
4. Add a generic trait bound for the roll function - such that your function accepts any type `T` - where `T` implements your trait!

6991 cargo run
  Finished dev [unoptimized + debuginfo] target(s) in 0.02s
    Running `target/debug/dungeons_and_dragons`
>> d20
You rolled a d20: 7
>> d2
You rolled a d2: 1
>> d10
You rolled a d10: 4
>> d8
You rolled a d8: 3
>> 
Goodbye!

When you think your program is working, you can use autotest to run some simple automated tests:

6991 autotest

When you are finished working on this exercise, you must submit your work by running give:

6991 give-crate

The recommended due date for this exercise is Week 7 Wednesday 21:00:00.

You must run give before Week 10 Friday 17:00:00 to obtain the marks for this exercise. Note that this is an individual exercise; the work you submit with give must be entirely your own.

In this exercise, you will be finishing a quick implementation of a program that uses some basic operations using trait objects.

You've been given a starter crate languages, which consists of the Greeting trait, and three implementations of it for the English, French and Spanish structs.

Your task is to complete the following tasks in main.rs such that it compiles and prints some basic output.

1. First, implement the From trait, such that you can convert a &str into a Box<dyn Greeting>. You can assume that only valid strings will be given. In a real codebase, you would want to handle errors (maybe by using the TryFrom trait), but for this exercise, you can assume that the input is valid.
2. Second, finish the implementation of the speak_all_greetings function, such that it prints out the greetings.

    6991 cargo run
    Compiling languages v0.1.0
    Finished dev [unoptimized + debuginfo] target(s) in 0.21s
     Running `target/debug/languages`
John says:
Hello!
Hola!
Jane says:
Bonjour!

When you think your program is working, you can use autotest to run some simple automated tests:

6991 autotest

When you are finished working on this exercise, you must submit your work by running give:

6991 give-crate

The recommended due date for this exercise is Week 7 Wednesday 21:00:00.

You must run give before Week 10 Friday 17:00:00 to obtain the marks for this exercise. Note that this is an individual exercise; the work you submit with give must be entirely your own.