Reading input basics in Rust - Mini Project: Build & Apply

Reading input basics

📖 Scenario: You are creating a simple Rust program that asks the user for their name and age. This is a common task when you want to interact with people using your program.

🎯 Goal: Build a Rust program that reads the user's name and age from the keyboard and stores them in variables.

📋 What You'll Learn

Use the std::io module to read input

Create variables to store the user's name and age

Trim the input to remove extra spaces or newlines

Convert the age input from a string to a number

💡 Why This Matters

🌍 Real World

Reading input from users is essential for interactive programs like games, quizzes, or command-line tools.

💼 Career

Many programming jobs require handling user input safely and correctly, especially in backend or systems programming.

1

Create variables to store user input

Write code to create two mutable variables called name and age as empty String values.

Rust

let mut name = String::new();
let mut age = String::new();
// Your code here

Need a hint?

Use String::new() to create empty strings for name and age.

2

Read user input for name and age

Add code to read input from the user into the variables name and age using io::stdin().read_line(&mut name) and io::stdin().read_line(&mut age).

Rust

use std::io;

fn main() {
    let mut name = String::new();
    let mut age = String::new();

    io::stdin().read_line(&mut name).expect("Failed to read name");
    io::stdin().read_line(&mut age).expect("Failed to read age");
    // Your code here
}

Need a hint?

Use io::stdin().read_line(&mut variable) to read input into each variable.

3

Trim input and convert age to number

Add code to trim whitespace from name and age. Then convert age from a string to an u32 number using age.trim().parse::() and store it in a new variable called age_num.

Rust

use std::io;

fn main() {
    let mut name = String::new();
    let mut age = String::new();

    io::stdin().read_line(&mut name).expect("Failed to read name");
    io::stdin().read_line(&mut age).expect("Failed to read age");

    let name = name.trim();
    let age_num: u32 = age.trim().parse().expect("Please type a number!");
    // Your code here
}

Need a hint?

Use trim() to remove spaces and parse() to convert the age string to a number.

4

Print the user's name and age

Write a println! statement to display the message: Hello, {name}! You are {age_num} years old. using the variables name and age_num.

Rust

use std::io;

fn main() {
    let mut name = String::new();
    let mut age = String::new();

    io::stdin().read_line(&mut name).expect("Failed to read name");
    io::stdin().read_line(&mut age).expect("Failed to read age");

    let name = name.trim();
    let age_num: u32 = age.trim().parse().expect("Please type a number!");

    println!("Hello, {}! You are {} years old.", name, age_num);
    // Your code here
}

Need a hint?

Use println!("Hello, {}! You are {} years old.", name, age_num); to show the message.