Pointers in Go

The type *T is a pointer to a T value. It's zero value is nil

var p *int creates a pointer to an int

& generates a pointer to its operand - its used to retrieve the address, and the address is what is stored * denotes the pointer's underlying value - this retrieves the value at an address (dereferencing)

a := 1          // define int
b := 2          // define int

ap = &a
 // set ap to address of a (&a)
 //   ap address    : 0x2101f1018 (ap, or the address of a)
 //   ap value      : 1 (*ap)
 //   ap own address: 0x5559a0 (&ap)

*ap = 3
 // change the value at address &a to 3
 //   ap address: 0x2101f1018
 //   ap value  : 3 (*ap)

a = 4
 // change the value of a to 4
 //   ap address: 0x2101f1018
 //   ap value  : 4 (*ap)

ap = &b
 // set ap to the address of b (&b)
 //   ap address: 0x2101f1020
 //   ap value  : 2 (*ap)

https://play.golang.org/p/wNAr8vqmU0z

In this case, ap is a *int, and thus cannot be directly assigned to an int (e.g. ap = 4)

TODO - pointer with functions in Go https://appliedgo.com/courses/128278/lectures/2652320

[[20200720112652-pointers]]

[[go]]