package main

import "fmt"

// A pointer holds the memory address of a value. The type *T is a pointer to a T value. Its zero value is nil.
func zeroval(ival int) {
	ival = 0
}

// To change the actual value that a pointer points to, we need to dereference the pointer.
func zeroptr(iptr *int) {
	*iptr = 0
}

func main() {
	i := 1
	fmt.Println("initial:", i)

	// zeroval will get a copy of i, so the original i is not affected.
	zeroval(i)
	fmt.Println("zeroval:", i)

	// zeroptr will get a pointer to i, so it can change the value of i through the pointer.
	zeroptr(&i)
	fmt.Println("zeroptr:", i)

	// We can also use the & operator to get the pointer of a variable.
	fmt.Println("pointer:", &i)
}