Building a Command-Line App

Combine functions, input, collections, and error handling into a small CLI project.

Learning objectives

• Read simple user input
• Store data in a vector
• Structure a small command-line program

Command-Line Thinking

A command-line app accepts text input and produces text output. Rust is a strong language for building fast and reliable CLI tools.

Project Structure

A small CLI can begin in one file. As the app grows, you can move code into modules.

Mini Project

The example below stores a few tasks in a vector and prints them as a simple task list.

Example code

fn main() {
    let mut tasks: Vec<String> = Vec::new();

    tasks.push(String::from("Learn ownership"));
    tasks.push(String::from("Practice structs"));
    tasks.push(String::from("Build a CLI app"));

    println!("Task List");
    for (index, task) in tasks.iter().enumerate() {
        println!("{}. {}", index + 1, task);
    }
}