什么是“静态”？在C中意味着什么？

问题描述

我已经在C代码的不同地方看到了 static 这个词；这就像C＃中的静态函数/类（实现在对象之间共享）吗？

I've seen the word static used in different places in C code; is this like a static function/class in C# (where the implementation is shared across objects)?

推荐答案

1. 函数内部的静态变量在调用之间保持其值。


2. 仅在其声明的文件中看到静态全局变量或函数

（1）是如果您是新手，那么您会遇到更多的外国话题，因此这里有个例子：

(1) is the more foreign topic if you're a newbie, so here's an example:

#include <stdio.h>

void foo()
{
    int a = 10;
    static int sa = 10;

    a += 5;
    sa += 5;

    printf("a = %d, sa = %d\n", a, sa);
}


int main()
{
    int i;

    for (i = 0; i < 10; ++i)
        foo();
}

此打印：

a = 15, sa = 15
a = 15, sa = 20
a = 15, sa = 25
a = 15, sa = 30
a = 15, sa = 35
a = 15, sa = 40
a = 15, sa = 45
a = 15, sa = 50
a = 15, sa = 55
a = 15, sa = 60

这在函数需要保持某些状态的情况下非常有用之间的调用，并且您不想使用全局变量。但是要当心，应该非常谨慎地使用此功能-它使您的代码不是线程安全的并且更难以理解。

This is useful for cases where a function needs to keep some state between invocations, and you don't want to use global variables. Beware, however, this feature should be used very sparingly - it makes your code not thread-safe and harder to understand.

（2）被广泛用作访问控制功能。如果您具有实现某些功能的.c文件，则通常仅向用户公开一些公共功能。其其余功能应设为 static ，以便用户无法访问它们。

(2) Is used widely as an "access control" feature. If you have a .c file implementing some functionality, it usually exposes only a few "public" functions to users. The rest of its functions should be made static, so that the user won't be able to access them. This is encapsulation, a good practice.

引用：

然后回答第二个问题问题，这与C＃中的情况不同。

And to answer your second question, it's not like in C#.

在C ++中， static 也用于定义类属性（在相同类的所有对象之间共享）和方法。在C语言中没有类，因此此功能无关。

In C++, however, static is also used to define class attributes (shared between all objects of the same class) and methods. In C there are no classes, so this feature is irrelevant.

这篇关于什么是“静态”？在C中意味着什么？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！