learngo/08-numbers-and-strings/01-numbers/exercises/07-circle-area/main.go

// For more tutorials: https://blog.learngoprogramming.com
//
// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//

package main

import (
	"fmt"
)

// ---------------------------------------------------------
// EXERCISE: Circle Area
//
//  Calculate the area of a circle from the given radius
//
// CIRCLE AREA FORMULA
//  area = πr²
//  https://en.wikipedia.org/wiki/Area#Circles
//
// HINT
//  For PI you can use `math.Pi`
//
// EXPECTED OUTPUT
//  go run main.go 10
//    radius: 10 -> area: 314.1592653589793
//
// BONUS EXERCISE!
//   1. Print the area as 314.16
//   2. To do that you need to use the correct Printf verb :)
//      Instead of `%g` verb below.
//
//   go run main.go 10
//     radius: 10 -> area: 314.16
// ---------------------------------------------------------

func main() {
	var (
		radius = 10.
		area   float64
	)

	// ADD YOUR CODE HERE
	// ...

	// DO NOT TOUCH THIS
	fmt.Printf("radius: %g -> area: %g\n", radius, area)
}