golang结构体指针(golang指针与非指针接收器)

What are Pointers in Golang?

Pointers are a fundamental concept in computer programming that enables a program to directly access a specific memory location. A pointer contains the memory address of a variable or another pointer. In Golang, a pointer is denoted by an asterisk (*) followed by the type of the variable being pointed to. When using pointers, a program can modify the value of a variable directly in its memory location without having to make a copy of the variable. This can be more efficient than copying large data structures when dealing with complex programs.

Declaring and Initializing a Pointer in Golang

To declare a pointer, the pointer variable should be declared using the asterisk (*) before the variable name. The variable that the pointer will reference is declared immediately after. For example,

var p *int

declares a pointer variable, p, that points to a memory location holding an integer. However, the pointer is not assigned any value yet, so it is referred to as a "nil" pointer.

To initialize a pointer, use the ampersand (&) operator to take the address of the variable you want to reference. For example,

var x int = 5
p = &x

assigns the memory address of x to the pointer variable p. Now p contains the memory address of x and can be used to directly access x's value without having to reassign the variable.

Using Pointers in Golang Structs

Pointers in Golang can also be used with structs. Structs in Golang are user-defined data structures that can contain a collection of related fields of different types. By using pointers in structs, we can modify the struct's fields directly without having to pass the entire struct around the program.

To declare a struct pointer in Golang, use the following syntax:

type Person struct {
    name string
    age  int
}

var p *Person

Here, we've declared a struct called Person containing a name and age field. We then declared a pointer variable p that points to a Person struct.

When initializing a pointer to a struct, the same syntax is used as declaring a pointer to any other variable. Use the ampersand operator to reference the memory address of the struct.

person := Person{"Alice", 24}
p = &person

In this example, we've declared a Person struct and assigned it to a variable named "person". We then initialized the pointer variable, p, to reference the memory address of the Person struct.

Once the pointer has been initialized, we can use the arrow (->) operator to access the fields of the struct. For example,

p.age = 25

changes the age field of the Person struct to 25 by modifying it directly in memory.

In conclusion, using pointers in Golang structs can be beneficial for large or complex programs as it enables modification of specific fields without having to copy the entire struct. By using pointers correctly, developers can write more efficient and scalable programs in Golang.