Go Structs and Methods

Go has no classes. A struct groups named fields, and a method is a function with a receiver written before its name. func (r Rect) Area() int means Area can be called on any Rect value.

package main

import "fmt"

type Rect struct {
  Width, Height int
}

func (r Rect) Area() int {
  return r.Width * r.Height
}

func main() {
  r := Rect{Width: 3, Height: 4}
  fmt.Println(r.Area())
}