Something about pointer and value in go

main.go

package main

import (
	"fmt"
)

type Test struct {
	A int
}

func testFn(a Test) Test {
	return a
}

func main() {
	a := Test{
		A: 1,
	}
	b := testFn(a)
	c := Test{
		A: 1,
	}
	d := a // copy inner with a new pointer
	d.A = 4
	fmt.Printf("%p, %p, %p, %p \n", &a, &b, &c, &d)
	fmt.Println(a)
	fmt.Println(d)
	m := make(map[Test]int)
	m[a] = 1
	m[c] = 2 // hash only care about the inner content
	fmt.Println(m)

	e := &a
	f := e
	fmt.Printf("%p, %p \n", &e, &f)
	e.A = 4 // auto deref
	fmt.Println(a)
	fmt.Println(f) // auto deref
}

// 0x40e020, 0x40e024, 0x40e028, 0x40e02c 
// {1}
// {4}
// map[{1}:2]
// 0x40c140, 0x40c148 
// {4}
// &{4}