RUST EXCERCISE - LINKED LIST

 

 LINKED LIST: 

• Creating a linked list in Rust

SOLUTION:

• use crate::List::*;
  
  enum List {
      Cons(u32, Box<List>),
      Nil,
  }
  
  impl List {
      fn new() -> List {
          Nil
      }
  
      fn prepend(self, elem: u32) -> List {
          Cons(elem, Box::new(self))
      }
      
      fn len(&self) -> i32 {
        fn get_len(tail: &List, _counter: i32) -> i32{
           match tail{
              Cons(_, tail) => get_len(tail, _counter+1),
              Nil => _counter
           }
        }
        get_len(self, 0)
      }
  
      fn stringify(&self) -> String {
  
         fn get_stringfy(tail: &List, mut strif:Vec<String>) -> String{
            match tail {
               Cons(head, tail) => {
                  let dis_as = format!("{}", head);
                  strif.push(dis_as);
                  get_stringfy(tail, strif)
               }
               Nil => {
                  strif.push("Nil".to_string());
                  strif.join(", ")
               }
            }
         }
         get_stringfy(self, vec![])
      }
  
      fn stringify_2(&self) -> String {
          fn get_stringfy_2(tail: &List, mut strif:String) -> String{
            match tail{
                Cons(head, tail) => {
                   let dis_as = format!("{}, ", head);
                   strif.push_str(&dis_as);
                   get_stringfy_2(tail, strif)
                }
                Nil => {
                   strif.push_str("Nil");
                   strif
                }
            }
      }
      get_stringfy_2(self, String::new())
      }
  }
  
  fn main() {
      let mut list = List::new();
  
      list = list.prepend(1);
      list = list.prepend(2);
      list = list.prepend(3);
  
      println!("linked list has length: {}", list.len());
      println!("{}", list.stringify());
      println!("{}", list.stringify_2());
  }