如何做阵列[100] = {0}设置整个阵列为0？ [英] how does array[100] = {0} set the entire array to 0?

问题描述

编译器如何填写字符数组值[100] = {0}; ？什么是神奇的背后？

How does the compiler fill values in char array[100] = {0};? What's the magic behind it?

我想知道编译器如何在内部进行初始化。

I wanted to know how internally compiler initializes.

推荐答案

这不是魔术。

在C中，它code的行为在C规格（的ç规格在线征求意见稿）：对于没有指定值的元素，编译器初始化指针为NULL，算术类型为零（递归适用这集合体）。

The behavior of this code in C is described in section 6.7.8.21 of the C specification (online draft of C spec): for the elements that don't have a specified value, the compiler initializes pointers to NULL and arithmetic types to zero (and recursively applies this to aggregates).

在C ++这个code的行为在C ++规范的第8.5.1.7（描述的的C网上草案++规范）：编译总初始化没有指定值的元素

The behavior of this code in C++ is described in section 8.5.1.7 of the C++ specification (online draft of C++ spec): the compiler aggregate-initializes the elements that don't have a specified value.

另外，还要注意在C ++中（但不是C），您可以使用空初始化列表，从而使编译器聚合初始化所有的数组中的元素：

Also, note that in C++ (but not C), you can use an empty initializer list, causing the compiler to aggregate-initialize all of the elements of the array:

char array[100] = {};

至于什么样的$ C $的c中的编译器可能会生成执行此操作时，看看这个问题：<一href=\"http://stackoverflow.com/questions/531477/strange-assembly-from-array-0-initialization/531490\">Strange从0阵列的初始化组装

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