Pointers in Go
Feb. 10, 2022, 7:38 p.m.
Vuong HuynhPointer is a data type in Go. It shows the address of a value. The pointer type is also called the reference type.
Example of a pointer: 0xc000126000. This is an address in a memory location.
Reference a value
Normally, we work with some value types such as integer or string. In order to get the pointer or the reference of that value, we can place the & keyword before the variable name to refer to its memory location. Or in other words, we use & to get the pointer of that value.
The syntax &variableName:
a := 111
fmt.Println(&a)This code prints out 0xc00010a000, which is the memory location of a, not the value of a (111)
Type of pointers
The type of pointers will be displayed with the * before the value type. Example: *int, *string.
a := 111
fmt.Printf("%T", &a)
fmt.Println()
b := "Hello"
fmt.Printf("%T", &b)This will print out
*int
*string
Dereference a pointer
When we have a pointer and want to get its value, we place the * before that pointer.
a := 111
fmt.Println(&a)
fmt.Println(*&a)
c := &a
fmt.Println(c)
fmt.Println(*c)It prints out
0xc000126000
111
0xc000126000
111
Change the value held by a pointer
When we have a pointer, we can change the value it is holding by dereferencing it.
a := 111
fmt.Println(a)
c := &a
*c = 222
fmt.Println(a)The result is:
111
222