Golang struct composition and polymorphism simple example

main.go

package main

import (
	"fmt"
)

type IAnimal interface {
	Talk()
	Info()
}
type Animal struct {
	name string
	age  int
}

type Cat struct {
	Animal
	x int
}

func (c Cat) Talk() {
	fmt.Printf("Meoww..\n")
}
func (c Cat) Info() {
	fmt.Printf("Cat name:%s age:%d x:%d \n", c.name, c.age, c.x)
}
func NewCat(name string, age int, x int) Cat {
	return Cat{Animal{name, age}, x}
}

type Dog struct {
	Animal
	y int
}

func (d Dog) Talk() {
	fmt.Printf("woof woof!\n")
}
func (d Dog) Info() {
	fmt.Printf("Dog name:%s age:%d y:%d \n", d.name, d.age, d.y)
}
func NewDog(name string, age int, y int) Dog {
	return Dog{Animal{name, age}, y}
}

func animalPrinter(animal IAnimal) {
	animal.Info()
	animal.Talk()
	fmt.Printf("\n")
}

func main() {
	var a1 IAnimal = NewCat("Sylvester", 6, 123)
	var a2 IAnimal = NewDog("Hector", 12, 41)

	animalPrinter(a1)
	animalPrinter(a2)
}

output.txt

PS D:\Code\go\src\playground> go run main.go
Cat name:Sylvester age:6 x:123 
Meoww..

Dog name:Hector age:12 y:41 
woof woof!