Floating point types in Rust - Mini Project: Build & Apply

Floating point types

📖 Scenario: You are working on a simple calculator program that needs to handle decimal numbers accurately. You will learn how to use floating point types in Rust to store and work with decimal numbers.

🎯 Goal: Create floating point variables, perform a calculation, and display the result.

📋 What You'll Learn

Create floating point variables with exact values

Use a configuration variable for precision

Perform a calculation using floating point variables

Print the final result with specified precision

💡 Why This Matters

🌍 Real World

Handling prices and taxes accurately is important in shopping apps, billing systems, and financial software.

💼 Career

Understanding floating point types and formatting is essential for software developers working with money, measurements, or scientific data.

1

Create floating point variables

Create two floating point variables called price and tax_rate with the exact values 19.99 and 0.07 respectively.

Rust

# Create floating point variables price and tax_rate
# Your code here

Need a hint?

Use let to create variables and specify the type f64 for floating point numbers.

2

Add a precision configuration variable

Create an integer variable called precision and set it to 2 to represent the number of decimal places to show.

Rust

let price: f64 = 19.99;
let tax_rate: f64 = 0.07;
# Create an integer variable precision and set it to 2
# Your code here

Need a hint?

Use usize type for the precision variable.

3

Calculate total price with tax

Create a floating point variable called total_price that calculates the total by adding price and the tax amount (price * tax_rate).

Rust

let price: f64 = 19.99;
let tax_rate: f64 = 0.07;
let precision: usize = 2;
# Calculate total_price as price plus price times tax_rate
# Your code here

Need a hint?

Use arithmetic operators to calculate the total price.

4

Print the total price with precision

Print the total_price rounded to precision decimal places using println! and format! macros.

Rust

let price: f64 = 19.99;
let tax_rate: f64 = 0.07;
let precision: usize = 2;
let total_price: f64 = price + (price * tax_rate);
# Print total_price with precision decimal places
# Your code here

Need a hint?

Use {:.2} in the format string to show two decimal places.