Understanding Rust's Copy Trait

Rust's ownership system is powerful, but it can sometimes be tricky when dealing with data that you want to reuse or pass around without transferring ownership. This challenge focuses on understanding and implementing the Copy trait, which allows types to be implicitly copied instead of moved. Mastering Copy is crucial for efficient Rust code and avoiding common ownership-related errors.

Problem Description

Your task is to create a custom struct in Rust and implement the Copy trait for it. This struct will represent a simple 2D point with x and y coordinates, both of which are integers. You will then demonstrate how the Copy trait affects the behavior of your struct when it's assigned, passed to functions, or returned from functions.

Requirements:

1. Define a struct named Point with two public fields: x and y, both of type i32.
2. Derive the Copy trait for the Point struct.
3. Derive the Clone trait as well. (While Copy implies Clone, explicitly deriving Clone is good practice and often done together).
4. Derive the Debug trait for easy printing of Point instances.
5. Write a main function that:
   • Creates an instance of Point.
   • Assigns this Point instance to a new variable. Observe that ownership is not transferred.
   • Passes a Point instance to a function that takes Point by value. Demonstrate that the original Point can still be used after the function call.
   • Have a function return a Point by value and assign it to a new variable.

Expected Behavior:

When you assign a Point to another variable or pass it to a function by value, the original Point should remain valid and usable. This is because Copy types are bitwise copied, creating an entirely new, independent value.

Examples

Example 1:

Input:
(No direct input, code execution demonstrates behavior)

Output:
Initial point: Point { x: 10, y: 20 }
After assignment: Point { x: 10, y: 20 }
Original point after passing to function: Point { x: 10, y: 20 }
Returned point: Point { x: 5, y: 15 }

Explanation:

The main function will create a Point p1. When p1 is assigned to p2, p2 gets a copy of p1's data. When p1 is passed to a function process_point, the function receives a copy. The original p1 is still available. A separate function create_point returns a new Point, which is then assigned to returned_p.

Constraints

• The Point struct must contain i32 for its x and y coordinates.
• The solution must be written entirely in Rust.
• The code should compile without any ownership or borrowing errors related to Point instances.

Notes

• Remember that types like integers (i32, u8, etc.), booleans (bool), characters (char), and floating-point numbers (f32, f64) already implement Copy. Tuples and arrays composed entirely of Copy types also implement Copy.
• The Copy trait is "shallow." It performs a bitwise copy of the data. This is safe and efficient for types that don't manage external resources (like heap-allocated memory, file handles, etc.). For types that do manage resources, you typically don't want them to be Copy.
• You will need to define helper functions to demonstrate passing by value and returning by value.
• Use println!("{:?}", ...) to print the Point instances.