How to Change the Values of an Existing Person in Your Rust Program

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# How to Change the Values of an Existing Person in Your Rust Program

What the reader will be able to do: Modify the `name` and `age` values of an existing `Human` struct instance using mutability.

## Prerequisites
- Basic understanding of Rust structs and mutability (from previous tutorials)
- Familiarity with `let` bindings and variable reassignment

## Steps

1. **Create a mutable `Human` instance**  
   In `src/main.rs`, define a `Human` with `mut`:
   ```rust
   let mut person = Human {
       name: String::from("Alice"),
       age: 30,
   };
   ```

2. **Modify the values directly**  
   Change the fields using dot notation:
   ```rust
   person.name = String::from("Bob");
   person.age = 25;
   ```

3. **Print the updated values**  
   ```rust
   println!("Name: {}", person.name);
   println!("Age: {}", person.age);
   ```

4. **Compile and run**  
   Execute:
   ```bash
   cargo run
   ```
   Expected output:
   ```
   Name: Bob
   Age: 25
   ```

## Pitfalls
- Forgetting `mut` in the `let` binding (causes compilation errors)
- Trying to modify immutable references (e.g., `&Human` instead of `&mut Human`)
- Not passing `&mut person` to functions (requires mutable reference)

## To go further
- Learn about Rust's `clone()` method for deep copying structs
- Explore how to implement `From` and `Into` traits for type conversion