Differences between pointers in different languages ​​and Go language pointers

What distinguishes pointers in Go from those in other languages ​​are: type safety, explicit dereferencing, prohibition of pointer arithmetic, and value semantics, which is different from reference semantics, where pointers contain references to values ​​instead of value itself.

Differences between pointers in different languages ​​and Go language pointers

In many programming languages, pointers are variables used to reference specific locations in memory. Pointers in Go language have the following main differences from pointers in other languages:

Type safety

Pointers in Go language are type safe. This means that a pointer can only point to its intended type. For example, the following code will compile with an error:

var i int
var p *string = &i // 编译时错误：无法将 int* 分配给 *string

Explicit dereference

Pointers must be explicitly dereferenced in the Go language. This can be achieved through the * operator. For example, the following code prints the int value referenced by a pointer:

package main

import "fmt"

func main() {
    i := 10
    p := &i

    fmt.Println(*p) // 输出：10
}

Pointer arithmetic

Pointer arithmetic is not allowed in the Go language. This means that you cannot use the or -- operators to increment or decrement the value of a pointer.

Value semantics

Go language pointers have value semantics. This means that the pointer variable itself stores the pointer value, not the value pointed to. This is different from reference semantics in other languages, where pointer variables store references to values.

Example

To further illustrate these differences, here is an example using C and Go to achieve the same functionality:

C

int main() {
    int i = 10;
    int *p = &i;

    printf("%d\n", i); // 输出：10
    printf("%d\n", *p); // 输出：10
    *p = 20; // 修改指针引用的值
    printf("%d\n", i); // 输出：20
}

Go

package main

import "fmt"

func main() {
    i := 10
    p := &i

    fmt.Println(i) // 输出：10
    fmt.Println(*p) // 输出：10
    *p = 20 // 修改指针引用的值
    fmt.Println(i) // 输出：20
}

In this example, the C code exhibits reference semantics, where pointer p directly modifies the value of i. The Go code exhibits value semantics, where the pointer p is an independent value and its modification does not affect the value of i.

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