Go language "Tenth article": GO Data structure: pointer

Go language pointers

Pointers are easy to learn in the go language, and using pointers in the go language makes it easier to perform some tasks. We all know that a variable is a handy placeholder for referencing a computer's memory address. The address of the go language is &, which is used before a variable to return the memory address of the corresponding variable, the following example shows the variable in memory address:

package"fmt"func main() {    varint10        fmt.Printf("变量的地址：%x\n", &a)}

The result of the above instance execution is:

变量的地址: 20818a220

What is a pointer
A pointer variable points to the memory address of a value, similar to a variable and constant, and requires a pointer to be declared before the pointer is used. The pointer declaration format is as follows:

var var_name *var-type

Var-type is a pointer type, var_name is a pointer variable, * is used to specify that the variable is a pointer, and the following is a valid pointer declaration:

var ip *int    /* 指向整形 */var fp *float32    /* 指向浮点型 */

How to use pointers

• Define pointer variables;
• Assigning values to pointer variables;
• Access to the value of the address in the pointer variable;

Precede the pointer type with an * sign (prefix) to get the content pointed to by the pointer.

package mainimport"fmt"func main() {   varint20   /* 声明实际变量 */   var ip *int        /* 声明指针变量 */   ip = &a  /* 指针变量的存储地址 */   fmt.Printf("a 变量的地址是: %x\n", &a  )   /* 指针变量的存储地址 */   fmt.Printf("ip 变量储存的指针地址: %x\n", ip )   /* 使用指针访问值 */   fmt.Printf("*ip 变量的值: %d\n", *ip )}

The result of the above example output is:

20

Go null pointer
When a pointer is defined and not assigned to any variable, its value is nil. The nil pointer is also called a null pointer, and nil is conceptually null, None, nil, and Null in other languages, all referring to 0 or null values. A pointer variable is usually abbreviated as PTR, as shown in the following example code:

package mainfunc main() {   var  ptr *int   fmt.Printf("ptr 的值为 : %x\n", ptr  )}

The result of the above example output is:

0

Null pointer judgment:

ifnil)     /* ptr 不是空指针 */ifnil)    /* ptr 是空指针 */

Go pointers more content
Next we will introduce more pointer applications in the GO language:

content	Description
Go pointer array	You can define an array of pointers to store addresses
Pointer to go pointing pointer	Go supports pointers pointing to pointers
Go to function pass pointer parameter	You can change the value of a function call by reference or by an address parameter

Go language "Tenth article": GO Data structure: pointer