Go language pointer
Go pointers are easy to learn in a language Go using pointers in the language makes it easier to perform some tasks.
Next, let’s learn Go language pointer step by step.
As we all know, a variable is an easy-to-use placeholder for referencing thecomputer’s memory address.
The address character of the Go language is &, when used in front ofa variable, the memory address of the corresponding variable is returned.
The following example demonstrates the in-memory address of a variable:
Example
package main
import "fmt"
func main() {
var a int = 10
fmt.Printf("variable address: %x\\n", &a )
}
The output result of executing the above code is:
variable address: 20818a220
Now we know what the memory address is and how to access it. Next we will introduce pointers in detail.
What is a pointer?
A pointer variable points to the memory address of a value.
Similar to variables and constants, you need to declare pointers before using them. The pointer declaration format is as follows:
var var_name *var-type
var-type is the pointer type, var_name is the pointer variable name``*`` is used to specify that the variable is used as a pointer. The following are valid pointer declarations:
var ip *int /* Pointing integer*/
var fp *float32 /* Pointing to floating point type */
In this case, this is a point to int and float32 pointer.
How to use pointers
Pointer usage process:
Define pointer variables.
Assign a value to the pointer variable.
Access the value in the pointer variable that points to the address.
Add before the pointer type * (prefix) to get what the pointer points to.
Example
package main
import "fmt"
func main() {
var a int= 20 /* Declare actual variables */
var ip *int /* Declare pointer variables */
ip = &a /* Storage address of pointer variable */
fmt.Printf("The address of variable a is: %x\\n", &a )
/* Storage address of pointer variable */
fmt.Printf("ip Pointer address for variable storage: %x\\n", ip )
/* Using pointers to access values */
fmt.Printf("*ip Value of variable: %d\\n", *ip )
}
The output of the above example is as follows:
The address of variable a is: 20818a220
The pointer address stored in the IP variable: 20818a220
*The value of the IP variable: 20
Go null pointer
When a pointer is defined and not assigned to any variable, its value is nil .
nil pointer is also called a null pointer.
nil conceptually and in other languages null 、 None 、 nil、 NULL similarly, they all refer to zero or null values.
A pointer variable is usually abbreviated to ptr .
View the following examples:
Example
package main
import "fmt"
func main() {
var ptr *int
fmt.Printf("The value of ptr is: %x\\n", ptr )
}
The output result of the above example is:
The value of ptr is: 0
Null pointer judgment:
if(ptr != nil) /* Ptr is not a null pointer */
if(ptr == nil) /* Ptr is a null pointer */
Go pointer more
Next, we will introduce to you Go more pointer applications in the language:
Content |
Description |
|---|---|
Go pointer array |
You can define an array of pointers to store addresses. |
A pointer to a pointer by a Go |
Go supports pointers to pointers |
Go passes pointer parameters to the function |
By passing parameters by reference or address, you can change the value of afunction when it is called |