Operator precedence in Go - Mini Project: Build & Apply

Operator precedence

📖 Scenario: Imagine you are calculating the total cost of items in a shopping cart with discounts and taxes. You need to understand how Go handles operator precedence to get the correct total.

🎯 Goal: Build a simple Go program that calculates the final price of an item after applying a discount and adding tax, using operator precedence correctly.

📋 What You'll Learn

Create variables for price, discount, and tax rate with exact values

Create a variable for discounted price using subtraction and multiplication

Calculate the final price by adding tax to the discounted price using correct operator precedence

Print the final price

💡 Why This Matters

🌍 Real World

Calculating prices with discounts and taxes is common in shopping and billing systems.

💼 Career

Understanding operator precedence helps avoid bugs in financial calculations and data processing.

1

Create initial price variables

Create three variables in Go: price with value 100.0, discount with value 0.2, and taxRate with value 0.1. Use type float64 for all.

Go

// Your code here

Need a hint?

Use var keyword to declare variables with type float64.

2

Calculate discounted price

Add a variable discountedPrice that calculates the price after discount using the formula price - price * discount.

Go

package main

import "fmt"

func main() {
    var price float64 = 100.0
    var discount float64 = 0.2
    var taxRate float64 = 0.1

    // Your code here
}

Need a hint?

Remember multiplication happens before subtraction.

3

Calculate final price with tax

Create a variable finalPrice that adds tax to the discounted price using the formula discountedPrice + discountedPrice * taxRate.

Go

package main

import "fmt"

func main() {
    var price float64 = 100.0
    var discount float64 = 0.2
    var taxRate float64 = 0.1

    var discountedPrice float64 = price - price * discount

    // Your code here
}

Need a hint?

Multiplication happens before addition, so no parentheses needed.

4

Print the final price

Use fmt.Printf to print the finalPrice with two decimal places, using the format string "Final price: %.2f\n".

Go

package main

import "fmt"

func main() {
    var price float64 = 100.0
    var discount float64 = 0.2
    var taxRate float64 = 0.1

    var discountedPrice float64 = price - price * discount
    var finalPrice float64 = discountedPrice + discountedPrice * taxRate

    // Your code here
}

Need a hint?

Use fmt.Printf with "%.2f" to format the float with two decimals.