pointer_vs_value.go

package main

type Foo struct {
    Bar string
}

// It does update Bar value for receiving struct
// since it receives an pointer value.
func (foo *Foo) ChangeBarPtr(bar string) {
	foo.Bar = bar
	println("inmethod foo.Bar: " + foo.Bar)
}

// Does not update Bar value for receiving struct
// since it receives a copy.
func (foo Foo) ChangeBarValue(bar string) {
	foo.Bar = bar
	println("inmethod foo.Bar: " + foo.Bar)
}

func main() {
	foo := Foo{
		Bar: "Bar 0",
	}
	println("foo.Bar: " + foo.Bar)

	foo.ChangeBarPtr("Bar 1")
	println("foo.Bar: " + foo.Bar)

	foo.ChangeBarValue("Bar 2")
	println("foo.Bar: " + foo.Bar)
}