Operator precedence in Rust - Mini Project: Build & Apply

Operator precedence

📖 Scenario: Imagine you are calculating the total cost of items in a shopping cart. You want to make sure the calculations happen in the right order so you get the correct total.

🎯 Goal: Build a Rust program that calculates the total cost using operator precedence rules correctly.

📋 What You'll Learn

Create variables with exact values

Use operator precedence in an expression

Print the final calculated total

💡 Why This Matters

🌍 Real World

Calculating prices in shopping carts or invoices requires correct operator precedence to avoid mistakes.

💼 Career

Understanding operator precedence is essential for writing correct calculations in software development, especially in finance and e-commerce.

1

Create item prices

Create three variables called apple_price, banana_price, and orange_price with values 2, 3, and 4 respectively.

Rust

let apple_price = 0;
let banana_price = 0;
let orange_price = 0;
// Your code here

Need a hint?

Use let to create variables and assign the exact numbers.

2

Create quantity variables

Create three variables called apple_qty, banana_qty, and orange_qty with values 3, 2, and 5 respectively.

Rust

let apple_price = 2;
let banana_price = 3;
let orange_price = 4;
let apple_qty = 0;
let banana_qty = 0;
let orange_qty = 0;
// Your code here

Need a hint?

Use let to create quantity variables with the exact numbers.

3

Calculate total cost with operator precedence

Create a variable called total_cost that calculates the total price by multiplying each price by its quantity and adding all results together. Use the expression: apple_price * apple_qty + banana_price * banana_qty + orange_price * orange_qty.

Rust

let apple_price = 2;
let banana_price = 3;
let orange_price = 4;
let apple_qty = 3;
let banana_qty = 2;
let orange_qty = 5;
let total_cost = 0; // Your code here

Need a hint?

Remember multiplication happens before addition without extra parentheses.

4

Print the total cost

Print the value of total_cost using println! with the exact text: Total cost: {total_cost} where {total_cost} is replaced by the variable value.

Rust

let apple_price = 2;
let banana_price = 3;
let orange_price = 4;
let apple_qty = 3;
let banana_qty = 2;
let orange_qty = 5;
let total_cost = apple_price * apple_qty + banana_price * banana_qty + orange_price * orange_qty;
// Your code here

Need a hint?

Use println!("Total cost: {}", total_cost); to print the result.