Exercise 1: Ownership Practice

Problem Statement

Identify and fix the ownership issues in the following code samples. The goal is to make all examples compile and run correctly without changing their intended functionality.

Learning Objectives

• Identify common ownership problems
• Apply appropriate solutions (cloning, borrowing, etc.)
• Understand the implications of move semantics

Starter Code

// Example 1: String ownership
fn main() {
    let s1 = String::from("hello");
    let s2 = s1;

    println!("{}, world!", s1); // Error: s1 has been moved
}

// Example 2: Function ownership
fn main() {
    let s = String::from("hello");
    takes_ownership(s);

    println!("After function call: {}", s); // Error: s has been moved
}

fn takes_ownership(some_string: String) {
    println!("Inside function: {}", some_string);
}

// Example 3: Vector ownership
fn main() {
    let v = vec![1, 2, 3, 4, 5];

    for i in v {
        println!("{}", i);
    }

    // Calculate and print the sum of elements in v
    let sum: i32 = v.iter().sum(); // Error: v has been moved in the for loop
    println!("Sum: {}", sum);
}

How to Run Your Code

1. First, modify the starter code in 01_ownership_practice_starter.rs to fix the ownership issues
2. Run your code from the bootcamp root directory with: cargo run --bin module2_01

Expected Output

After fixing the ownership issues, your code should produce the following outputs:

Example 1:

hello, world!

Example 2:

Inside function: hello
After function call: hello

Example 3:

1
2
3
4
5
Sum: 15

Tips

• Consider when to use clone() to duplicate data
• Look for opportunities to use references (&) instead of moving values
• Remember that for loops take ownership of collections by default unless you iterate over references