Interface in go

[[go]]
## How to Implement Interfaces

In Go, to implement an interface, a type must define all methods declared by the interface. Implementation is implicit, meaning no keyword (such as `implements`) is needed.

package main
import (
"fmt"
"math"
)

// Define the interface
type Shape interface {
Area() float64
Perimeter() float64
}

// Circle type that implements the Shape interface
type Circle struct {
radius float64
}

// Rectangle type that implements the Shape interface
type Rectangle struct {
length, width float64
}
func (c Circle) Area() float64 {
return math.Pi * c.radius * c.radius
}

func (c Circle) Perimeter() float64 {
return 2 * math.Pi * c.radius
}

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

func (r Rectangle) Perimeter() float64 {
return 2 * (r.length + r.width)
}

// Main function to demonstrate the interface
func main() {
var s Shape

s = Circle{radius: 5}
fmt.Println("C Area:", s.Area())
fmt.Println("C Perimeter:", s.Perimeter())

s = Rectangle{length: 4, width: 3}
fmt.Println("R Area:", s.Area())
fmt.Println("R Perimeter:", s.Perimeter())
}