1. Guessing Game
  2. Common Programming Concepts
    1. Variables and Mutability
    2. Data Types
    3. Function
    4. Control Flow
  3. Understanding Ownership
    1. References and Borrowing
    2. The Slice Type
  4. Using Structs
    1. An Example Program Using Structs
    2. Method Syntax
  5. Enums and Pattern Matching
    1. The match Control Flow Operator
    2. Concise Control Flow with if let
  6. Managing Growing Projects with Packages, Crates, and Modules
    1. Defining Modules to Control Scope and Privacy
    2. Paths for Referring to an Item in the Module Tree
    3. Bringing Paths into Scope with the use Keyword
    4. Separating Modules into Different Files
  7. Common Collections
    1. Storing UTF-8 Encoded Text with Strings
    2. Storing Keys with Associated Values in Hash Maps
  8. Error Handling
    1. Unrecoverable Errors with panic!
    2. Recoverable Errors with Result
  9. Generic Types, Traits, and Lifetimes
    1. Traits: Defining Shared Behavior
    2. Generics Rust by Example
      1. Functions
      2. Implementation
  10. Writing Automated Tests
  11. Object Oriented Programming
  12. Adding dependancies
  13. Option Take
  14. RefCell
  15. mem
  16. Data Structure
    1. Linked List
    2. Binary search tree
    3. N-ary Sum tree
  17. Recipe
    1. Semi colon
    2. Calling rust from python
    3. Default
    4. Crytocurrency With rust
    5. Function chaining
    6. Question Mark Operator
    7. Tests with println
    8. lib and bin
    9. Append vector to hash map
    10. Random Number
    11. uuid4
    12. uwrap and option
  18. Blockchain with Rust
  19. Near Protocol
    1. Startup code
    2. Couter
    3. Status
    4. Avrit
  20. Actix-web

Object Oriented Programming

Encapsulation that Hides Implementation Details
Another aspect commonly associated with OOP is the idea of encapsulation, which means that the implementation details of an object aren’t accessible to code using that object. Therefore, the only way to interact with an object is through its public API; code using the object shouldn’t be able to reach into the object’s internals and change data or behavior directly.

pub struct AveragedCollection {
    list: Vec<i32>,
    average: f64,

An AveragedCollection struct that maintains a list of integers and the average of the items in the collection.

The struct is marked pub so that other code can use it, but the fields within the struct remain private. This is important in this case because we want to ensure that whenever a value is added or removed from the list, the average is also updated. We do this by implementing add, remove, and average methods on the struct.

Filename: src/

fn main() {
pub struct AveragedCollection {
    list: Vec<i32>,
    average: f64,

impl AveragedCollection {
    pub fn add(&mut self, value: i32) {

    pub fn remove(&mut self) -> Option<i32> {
        let result = self.list.pop();
        match result {
            Some(value) => {
            None => None,

    pub fn average(&self) -> f64 {

    fn update_average(&mut self) {
        let total: i32 = self.list.iter().sum();
        self.average = total as f64 / self.list.len() as f64;

We leave the list and average fields private so there is no way for external code to add or remove items to the list field directly; otherwise, the average field might become out of sync when the list changes. The average method returns the value in the average field, allowing external code to read the average but not modify it.

If encapsulation is a required aspect for a language to be considered object oriented, then Rust meets that requirement. The option to use pub or not for different parts of code enables encapsulation of implementation details.

Inheritance as a Type System and as Code Sharing
Inheritance is a mechanism whereby an object can inherit from another object’s definition, thus gaining the parent object’s data and behavior without you having to define them again.

If a language must have inheritance to be an object-oriented language, then Rust is not one. There is no way to define a struct that inherits the parent struct’s fields and method implementations. However, if you’re used to having inheritance in your programming toolbox, you can use other solutions in Rust, depending on your reason for reaching for inheritance in the first place.

To many people, polymorphism is synonymous with inheritance. But it’s actually a more general concept that refers to code that can work with data of multiple types. For inheritance, those types are generally subclasses.
Rust instead uses generics to abstract over different possible types and trait bounds to impose constraints on what those types must provide. This is sometimes called bounded parametric polymorphism.

Rust takes a different approach, using trait objects instead of inheritance. Let’s look at how trait objects enable polymorphism in Rust.

Using Trait Objects That Allow for Values of Different Types