Constants in Go - Mini Project: Build & Apply

Using Constants in Go

📖 Scenario: You are creating a simple program to calculate the area of a circle. You will use a constant for the value of Pi to keep your code clean and easy to update.

🎯 Goal: Build a Go program that defines a constant for Pi, uses it to calculate the area of a circle with a given radius, and prints the result.

📋 What You'll Learn

Create a constant named Pi with the value 3.14

Create a variable named radius with the value 5

Calculate the area of the circle using the formula Pi * radius * radius

Print the area with a descriptive message

💡 Why This Matters

🌍 Real World

Constants are used in programs to store values that do not change, like mathematical constants, configuration values, or fixed settings.

💼 Career

Understanding constants is important for writing clear, maintainable code in any software development job.

1

Create the radius variable

Create a variable called radius and set it to 5.

Go

# Your code here

Need a hint?

Use radius := 5 inside the main function.

2

Define the Pi constant

Define a constant named Pi with the value 3.14 above the main function.

Go

package main

import "fmt"

const Pi = 3.14

func main() {
    radius := 5
    // Your code here
}

Need a hint?

Write const Pi = 3.14 before the main function.

3

Calculate the area

Create a variable called area and set it to the calculation Pi * radius * radius inside the main function.

Go

package main

import "fmt"

const Pi = 3.14

func main() {
    radius := 5
    // Your code here
}

Need a hint?

Use area := Pi * float64(radius) * float64(radius) to calculate the area.

4

Print the area

Print the message "Area of the circle:" followed by the value of area using fmt.Println.

Go

package main

import "fmt"

const Pi = 3.14

func main() {
    radius := 5
    area := Pi * float64(radius) * float64(radius)
    // Your code here
}

Need a hint?

Use fmt.Println("Area of the circle:", area) to print the result.