gobyexample/structs/structs.go

package structs

import (
	"fmt"
	"math"
)

type ShapeMetadata struct {
	Id   int
	Name string
}

type Shape interface {
	Area() float64
	Perimeter() float64
}

type Square struct {
	ShapeMetadata
	Size float64
}

type Rectangle struct {
	ShapeMetadata
	Length, Breadth float64
}

type Triangle struct {
	ShapeMetadata
	A, B, C float64
}

func (s *Square) Area() float64 {
	return s.Size * s.Size
}

func (s *Square) Perimeter() float64 {
	return 4 * s.Size
}

func (r *Rectangle) Area() float64 {
	return r.Length * r.Breadth
}

func (r *Rectangle) Perimeter() float64 {
	return 2 * (r.Length + r.Breadth)
}

func (t *Triangle) Area() float64 {
	s := (t.A + t.B + t.C) / 2
	area := math.Sqrt(s * (s - t.A) * (s - t.B) * (s - t.C))
	return area
}

func (t *Triangle) Perimeter() float64 {
	return t.A + t.B + t.C
}

func Structs() {
	sq := Square{
		ShapeMetadata: ShapeMetadata{
			Id:   0,
			Name: "mysquare",
		},
		Size: 10.0,
	}

	rect := Rectangle{
		ShapeMetadata: ShapeMetadata{
			Id:   0,
			Name: "myrectangle",
		},
		Length:  10,
		Breadth: 5,
	}

	tri := Triangle{
		ShapeMetadata: ShapeMetadata{
			Id:   0,
			Name: "mytriangle",
		},
		A: 2,
		B: 2,
		C: 2,
	}

	fmt.Printf("Triangle: Area = %.2f Perimeter = %.2f\n", tri.Area(), tri.Perimeter())
	fmt.Printf("Rectangle: Area = %.2f Perimeter = %.2f\n", rect.Area(), rect.Perimeter())
	fmt.Printf("Square: Area = %.2f Perimeter = %.2f\n", sq.Area(), sq.Perimeter())
}