Chapter 1.3: Hello, Cargo!

Overview

In this section of the Rust Programming Language Book, we will explore Cargo, Rust's official package manager and build system. Cargo simplifies project management, making it easier to build, test, and manage dependencies for Rust projects.

Key Concepts

What is Cargo?

• Cargo is the official package manager for Rust.
• It handles various tasks such as:
  • Building Rust projects
  • Managing project dependencies
  • Running tests
  • Generating documentation

Creating a New Project with Cargo

• To create a new Rust project, use the command:

cargo new project_name

• This command creates a new directory named project_name with a basic project structure, including:
  • A src folder containing a main.rs file
  • A Cargo.toml file which contains metadata about the project

Project Structure

• src/main.rs: This is the main source file where the code resides.
• Cargo.toml: This file includes:
  • Project name
  • Version
  • Author information
  • Dependencies

Building and Running the Project

• To build the project, navigate to the project folder and run:

cargo build

• To run the project, use:

cargo run

• When you run cargo run, it automatically builds the project if there are any changes.

Managing Dependencies

• You can add dependencies in the Cargo.toml file under the [dependencies] section. For example:

[dependencies]
rand = "0.8"

• After adding a dependency, run cargo build to download and compile the necessary packages.

Example

Here’s a brief example of how to create and run a simple Rust project with Cargo:

1. Create a new project:
2. Open src/main.rs and modify it:
3. Build and run the project:
4. Output:

Hello, Cargo!

cargo run

fn main() {
    println!("Hello, Cargo!");
}

cargo new hello_cargo
cd hello_cargo

Conclusion

Cargo is an essential tool for Rust developers, as it greatly simplifies project management and dependency handling. By mastering Cargo, you can efficiently build and maintain robust Rust applications.