package main

import "fmt"

type Shape interface {
  Area() float64
  Name() string
}

type triangle struct {
  base   float64
  height float64
}

type rectangle struct {
  length float64
  width  float64
}

type square struct {
  side float64
}

func (t triangle) Area() float64 {
  return (t.base * t.height) / 2
}

func (t triangle) Name() string {
  return "triangle"
}

func (r rectangle) Area() float64 {
  return r.length * r.width
}

func (r rectangle) Name() string {
  return "rectangle"
}

func (s square) Area() float64 {
  return s.side * s.side
}

func (s square) Name() string {
  return "square"
}

func printShapeDetails(shapes ...Shape) {
  for _, item := range shapes {
    fmt.Printf("The area of %s is %.2f\n", item.Name(), item.Area())
  }
}

func main() {

  t := triangle{15.5, 20.1}
  r := rectangle{20, 10}
  s := square{10}

  printShapeDetails(t, r, s)

}