Interfaces.go

package main

import (
	"fmt"
)

// Defining a interface

type User interface {
	PrintName(name string)
}

type Vehicle interface {
	Alert() string
}

// Create type for interface

type Usr int

type Car struct{}

// Implement interface function in type

func (usr Usr) PrintName(name string) {
	fmt.Println("User Id:\t", usr)
	fmt.Println("User Name:\t", name)
}

func (c Car) Alert() string {
	return "Hup! Hup!"
}

// Define an empty interface - Often used for functions that accepts any type

func Print(a ...interface{}) (n int, err error) {
	return fmt.Println(a...)
}

func main() {
	var user1 User
	user1 = Usr(1)
	user1.PrintName("Gabriel")
	c := Car{}
	fmt.Println(c.Alert())
	Print(20)
	Print("Hello world")
}