## lunch_queue
### Instructions
An API will have to be created to organize a queue of people.
Using the given code declare the following functions:
- `new` which will initialize the `Queue`
- `add` which receives the person's information, so it can be added to the `Queue`
- `invert_queue` which inverts the queue of persons
- `rm` , which will remove the person who finished ordering their food.
The removal should respect a FIFO system (first in first out). This function should return a tuple wrapped in an `Option` with the information of the removed person (check the usage)
- `search` , which returns a tuple with the information of a given person `id`
You must also create a type called `Link` . This will be the connection of the structures `Queue` and `Person` .
Do not forget that this will be a recursion type and it must point to `None` if there is no persons.
### Notions
- [enum ](https://doc.rust-lang.org/rust-by-example/custom_types/enum.html )
- [Box ](https://doc.rust-lang.org/book/ch15-01-box.html )
- [std::option ](https://doc.rust-lang.org/std/option/ )
### Expected Function adn Structures
```rust
pub struct Queue {
pub node: Link,
}
pub type Link =
pub struct Person {
pub id: i32,
pub name: String,
}
impl Queue {
pub fn new() -> Queue {}
pub fn add(& mut self, t: String, name: String) {}
pub fn invert_queue(& mut self) {}
pub fn rm(& mut self) -> Option< String > {}
pub fn search(& self) -> Option< (String, String)> {}
}
```
### Usage
Here is a program to test your function:
```rust
fn main() {
let mut list = Queue::new();
list.add(String::from("Marie"), 20);
list.add(String::from("Monica"), 15);
list.add(String::from("Ana"), 5);
list.add(String::from("Alice"), 35);
println!("{:?}", list);
println!("{:?}", list.search("Marie"));
println!("{:?}", list.search("Alice"));
println!("{:?}", list.search("someone"));
println!("removed {:?}", list.rm());
println!("list {:?}", list);
list.invert_queue();
println!("invert {:?}", list);
}
```
And its output:
```console
$ cargo run
Queue { node: Some(Person { name: "Alice", discount: 35, next_person: Some(Person { name: "Ana", discount: 5, next_person: Some(Person { name: "Monica", discount: 15, next_person: Some(Person { name: "Marie", discount: 20, next_person: None }) }) }) }) }
Some(("Marie", 20))
Some(("Alice", 35))
None
removed Some(("Marie", 20))
list Queue { node: Some(Person { name: "Alice", discount: 35, next_person: Some(Person { name: "Ana", discount: 5, next_person: Some(Person { name: "Monica", discount: 15, next_person: None }) }) }) }
invert Queue { node: Some(Person { name: "Monica", discount: 15, next_person: Some(Person { name: "Ana", discount: 5, next_person: Some(Person { name: "Alice", discount: 35, next_person: None }) }) }) }
$
```
