/*
* Program illustrating the use of pointers in Go.
* In particular, this program get the address of a struct
* and uses that as an alias for the struct
* @author gtowell
* created: July 29, 2021
 */
package main

import "fmt"

// A simple struct
type Astruct struct {
	aaa int
	bbb string
}

// tostring method for the struct
func (p Astruct) String() string {
	return fmt.Sprintf("aaa:%d bbb:<<%v>>", p.aaa, p.bbb)
}

func main() {
	item := Astruct{aaa: 5, bbb: "20"}
	itemcopy := item
	itemcopy.aaa *= 4
	fmt.Printf("Item:%v\n", item)
	fmt.Printf("Copy:%v\n", itemcopy) // note that the item and the coy are different!!

	itemptr := &item              // the & operator get the address of "item"
	itemptr.aaa *= 4              // sets the value of the aaa field in the thing pointed to by itemptr.   This is exactly item!!!
	fmt.Printf("Item:%v\n", item) // the value of aaa in item has changed
	fmt.Printf("Ptr :%v  %p \n", itemptr, itemptr)
}