package main

import (
	"fmt"
	"math"
)

func main() {
	printNumericValue(1)
	// prints "int"

	printNumericValue("1")
	// prints "string"

	printNumericValue(struct{}{})
	// prints "struct {}"
}

// Interfaces
type shape interface {
	area() float64
	perimeter() float64
}

type rect struct {
	width, height float64
}

func (r rect) area() float64 {
	return r.width * r.height
}
func (r rect) perimeter() float64 {
	return 2*r.width + 2*r.height
}

type circle struct {
	radius float64
}

func (c circle) area() float64 {
	return math.Pi * c.radius * c.radius
}
func (c circle) perimeter() float64 {
	return 2 * math.Pi * c.radius
}

// Type Switches
func printNumericValue(num interface{}) {
	switch v := num.(type) {
	case int:
		fmt.Printf("%T\n", v)
	case string:
		fmt.Printf("%T\n", v)
	default:
		fmt.Printf("%T\n", v)
	}
}