Rust - lesson 1 | HackIndia Skills

Key point

One idea

Rust feels strict because the compiler checks your code before users hit bugs. Treat each error as a small task list: where it happened, what Rust expected, and what you can change.

What Cargo gives you

Cargo is Rust’s project tool. It creates the folder, stores project settings, builds your code, runs it, and later helps you add crates.

For your HackIndia submission, Cargo matters because reviewers can clone your repo and run the same commands you ran.

Your to-do

Start a CLI project

Do each one yourself, then tap it to tick it off. The ticks are only a checklist for you: they are not marked or scored.

Open a terminal in the folder where you keep projects.
Create a new Rust app with Cargo.
Move into the project folder.
Run the starter program once.
Check the code without building a final binary.

0 of 5 done

cargo new rust-attendance-cli
cd rust-attendance-cli
cargo run
cargo check

Example

First useful output

Open src/main.rs and replace the starter code. Keep it simple for now. The goal today is to see the edit-check-run loop.

fn main() {
    let course = "Data Structures";
    let present = 42;

    println!("{} attendance count: {}", course, present);
}

Your to-do

Use the loop

Do each one yourself, then tap it to tick it off. The ticks are only a checklist for you: they are not marked or scored.

Edit one small thing in src/main.rs.
Run cargo check before cargo run.
Read the first compiler error from top to bottom.
Fix one issue at a time.
Run cargo run only after cargo check passes.

0 of 5 done

cargo check
cargo run

Common mistake

Do not fight every line

Beginners often try to fix all errors at once. That creates more confusion.

Start with the first real error in your file. Later errors may disappear after the first fix.

Example

Read an error

Try this broken code for one minute. It is safe. You are practising how to read the compiler.

fn main() {
    let marks = 88
    println!("Marks: {}", marks);
}

// Run:
// cargo check

// You should see an error near the missing semicolon.
// Fix it:
// let marks = 88;

Tip

Ask for help well

When you use ChatGPT, Gemini, or Claude, paste the exact error and the small code block around it. Ask for the smallest fix and the reason.

Check the answer yourself. It should explain the compiler message, not rewrite your full project without asking.

Prompt:
I am learning Rust. Explain this compiler error in simple words.
Give the smallest fix only.
Here is my code and error:
<paste code and cargo check output>

Your to-do

Do this now

Do each one yourself, then tap it to tick it off. The ticks are only a checklist for you: they are not marked or scored.

Create a new Cargo project named rust-attendance-cli.
Change src/main.rs to print one useful line for a CLI idea you may build.
Run cargo check, then cargo run.
Break the code once, read the first error, and fix it.
Commit the working starter project if you already use Git.

0 of 5 done

git init
git add .
git commit -m "Start Rust CLI project"

Make the compiler your teammate

One idea

What Cargo gives you

Start a CLI project

First useful output

Use the loop

Do not fight every line

Read an error

Ask for help well

Do this now

Quick check