the-way-to-go_ZH_CN/eBook/exercises/chapter_10/rectangle.go

// rectangle.go
package main

import "fmt"

type Rectangle struct {
	length, width int
}

func (r *Rectangle) Area() int {
	return r.length * r.width
}

func (r *Rectangle) Perimeter() int {
	return 2 * (r.length + r.width)
}

func main() {
	r1 := Rectangle{4, 3}
	fmt.Println("Rectangle is: ", r1)
	fmt.Println("Rectangle area is: ", r1.Area())
	fmt.Println("Rectangle perimeter is: ", r1.Perimeter())
}

/* Output:
Rectangle is:  {4 3}
Rectangle area is:  12
Rectangle perimeter is:  14
*/