Handling input values in Rust - Mini Project: Build & Apply

Handling input values

📖 Scenario: You are creating a simple Rust program that asks the user for their age and then tells them if they are old enough to vote.

🎯 Goal: Build a Rust program that reads an input value from the user, converts it to a number, and checks if the user is 18 or older.

📋 What You'll Learn

Use std::io::stdin() to read input

Convert the input string to an u32 number

Use an if statement to check the age

Print a message based on the age

💡 Why This Matters

🌍 Real World

Reading and handling user input is essential for interactive programs like command-line tools and games.

💼 Career

Many programming jobs require you to safely get and use input from users or other sources.

1

Create a variable to store user input

Create a mutable variable called input of type String and initialize it with String::new().

Rust

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

Need a hint?

Use let mut input = String::new(); to create an empty string for input.

2

Read input from the user

Use std::io::stdin().read_line(&mut input).expect("Failed to read line") to read the user's input into the input variable.

Rust

fn main() {
    let mut input = String::new();
    std::io::stdin().read_line(&mut input).expect("Failed to read line");
    // Your code here
}

Need a hint?

Use read_line to get input from the user and store it in input.

3

Convert input string to a number

Create a variable called age and set it to input.trim().parse::().expect("Please type a number!") to convert the input string to a number.

Rust

fn main() {
    let mut input = String::new();
    std::io::stdin().read_line(&mut input).expect("Failed to read line");
    let age = input.trim().parse::().expect("Please type a number!");
    // Your code here
}

Need a hint?

Use trim() to remove whitespace and parse::() to convert to a number.

4

Check age and print message

Use an if statement to check if age is 18 or more. If yes, print "You are old enough to vote!". Otherwise, print "You are not old enough to vote.".

Rust

fn main() {
    let mut input = String::new();
    std::io::stdin().read_line(&mut input).expect("Failed to read line");
    let age = input.trim().parse::().expect("Please type a number!");
    if age >= 18 {
        println!("You are old enough to vote!");
    } else {
        println!("You are not old enough to vote.");
    }
    // Your code here
}

Need a hint?

Use if age >= 18 to check the age and println! to show the message.