Pointers in Go

Suppose you have a variable:

age := 20

Using &age you get the pointer to the variable, its memory address.

When you have the pointer to the variable, you can get the value it points to by using the * operator:

age := 20
ageptr = &age
agevalue = *ageptr

This is useful when you want to call a function and pass the variable as a parameter. Go by default copies the value of the variable inside the function, so this will not change the value of age:

func increment(a int) {
	a = a + 1
}

func main() {
	age := 20
	increment(age)

	//age is still 20
}

You can use pointers for this:

func increment(a *int) {
	*a = *a + 1
}

func main() {
	age := 20
	increment(&age)

	//age is now 21
}