pass-by-reference.go

package main

import (
	"fmt"
)

//Person type to repersent a person
type Person struct {
	FirstName string
	LastName  string
	Age       int
}

//Pointer to person struct is receiver for birthday function
//birthday increment person's age by 1
func (p *Person) birthday() {
	p.Age++
}

//add1 adds 1 to an integer
func add1(a *int) {
	*a = *a + 1
}

func main() {

	//Basic types
	a := 10
	fmt.Printf("\"a\" value before calling \"add1\" : %d\n", a)
	add1(&a)
	fmt.Printf("\"a\" value after calling \"add1\" : %d\n", a)

	//User defined types
	person := &Person{FirstName: "John", LastName: "Doe", Age: 30}
	fmt.Printf("Person's age before birthday : %d\n", person.Age)
	person.birthday()
	fmt.Printf("Person's age after birthday : %d\n", person.Age)
}