public/subjects/borrow_box/README.md

borrow box

Instructions

You will have to create a CRUD functionality. Therefore creating the following functions :

• new, that receives two players and initializes them with a name and a score. This functions should return the structure wrapped in a Box.

• read_winner, returns a tuple with the name and the score of the player who is winning. In case none of the players are winning, it should return the same tuple with the string "Same score! tied" and the tied score.

  • update_score, that receives the name of a player. This function should increment the score of the player. The score should only be increased if it does not pass the nbr_of_games. Example: if the nbr_of_games is 3 then the game should be best out of three. So if one play as 2 wins then he is the winner and the function should not increase the score anymore for either players.

• delete, that takes the ownership of the boxed game and returning a string : "Game deleted: id -> 0".

Expected Function

#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Game {
    // expected public fields
}
impl Game {
    pub fn new(i: u32, pl1: String, pl2: String, n: u16) -> Box<Game> {}
    pub fn read_winner(&self) -> (String, u16) {}
    pub fn update_score(&mut self, user_name: String) {}
    pub fn delete(self) -> String {}
}

Usage

Here is a program to test your function

fn main() {
    let mut game = Game::create_game(0, String::from("Joao"), String::from("Susana"), 5);
    println!("{:?}", game.read_winner());
    // output : ("Same score! tied", 0)

    game.update_score(String::from("Joao"));
    game.update_score(String::from("Joao"));
    game.update_score(String::from("Susana"));
    game.update_score(String::from("Susana"));
    println!("{:?}", game.read_winner());
    // output : ("Same score! tied", 2)

    game.update_score(String::from("Joao"));
    // this one will not count because it already 5 games played, the nbr_of_games
    game.update_score(String::from("Susana"));
    
    println!("{:?}", game.read_winner());
    // output : ("Joao", 3)

    game.delete();
    println!("{:?}", game.delete());
    // output : "game deleted: id -> 0"

    // game.read_winner();
    // this will give error
    // because the game was dropped, no longer exists on the heap
}

And its output:

student@ubuntu:~/[[ROOT]]/test$ cargo run
("Same score! tied", 0)
("Same score! tied", 2)
("Joao", 3)
"game deleted: id -> 0"
student@ubuntu:~/[[ROOT]]/test$

Notions

• https://doc.rust-lang.org/book/ch15-01-box.html