package main

import "fmt"

type Counter struct {
	value int
}

// pointer receiver
func (c *Counter) Increment() {
	c.value++
}

// value receiver
func (c Counter) String() string {
	return fmt.Sprintf("Counter value: %d", c.value)
}

func main() {
	c := Counter{}
	fmt.Println(c)
	c.Increment()
	fmt.Println(c)
}