How to do it...

1. Create a Rust project to work on during this chapter with cargo new chapter-one
2. Navigate to the newly created chapter-one folder. For the rest of this chapter, we will assume that your command line is currently in this directory
3. Inside the src folder, create a new folder called bin
4. Delete the generated lib.rs file, as we are not creating a library
5. In the src/bin folder, create a file called concat.rs
6. Add the following code and run it with cargo run --bin concat:

1  fn main() {
2   by_moving();
3   by_cloning();
4   by_mutating();
5  }
6
7  fn by_moving() {
8   let hello = "hello ".to_string();
9   let world = "world!";
10
11   // Moving hello into a new variable
12   let hello_world = hello + world;
13   // Hello CANNOT be used anymore
14   println!("{}", hello_world); // Prints "hello world!"
15  }
16
17  fn by_cloning() {
18   let hello = "hello ".to_string();
19   let world = "world!";
20
21   // Creating a copy of hello and moving it into a new variable
22   let hello_world = hello.clone() + world;
23   // Hello can still be used
24   println!("{}", hello_world); // Prints "hello world!"
25  }
26
27  fn by_mutating() {
28   let mut hello = "hello ".to_string();
29   let world = "world!";
30
31   // hello gets modified in place
32   hello.push_str(world);
33   // hello is both usable and modifiable
34   println!("{}", hello); // Prints "hello world!"
35  }