C中= {0}的长版本是什么？
我被问到这个问题：
= { 0 }是更长代码的“快捷方式”？
因此，经过我的C书的多次搜索和搜索之后，我知道它对聚合初始化所做的一切，但如果我想编写这段代码的较长版本会怎样。 以下是该程序的实际代码，以防万一
static char vid[25][100] = { 0 } ;
long版本是一个初始化数组所有成员的循环：
for (int i = 0; i < ARRAY_SIZE; ++i) { myArray[i] = 0; }
编译器可能会生成对memset函数的调用，该函数可能包含也可能不包含此naive循环的更优化版本。
但就像迪特里希指出的那样，在你在问题中展示的例子中，你是在声明一个static数组。 这让事情变得复杂一些。 未初始化的静态数据放在可执行文件的一个特殊部分，称为.bss部分，并且C和C ++标准都要求将其默认初始化为零。 如果显式初始化数据，则链接器会将其放入可执行文件的.data部分。 显式初始化为0有点特殊情况。 智能链接器将省略显式初始化器并将数据放在.bss部分中。 哑联系人仍然可以将数据放在.data部分中。 因此，最好不要使用静态链接显式地初始化对象。
长版本（你将很难得到更长的时间）：
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{'\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0','\0'} };
也就是说，decl是静态的，因此首先放在零初始化的内存中，所以这有点多余，但至少你知道它看起来像什么。
该标准没有定义如何进行归零，因此它的具体实现。 在实践中，对于局部变量，编译器通常会生成memset / RtlZeroMemory / RtlZeroMemory 为了这。 对于static / globals，不需要代码，因为变量将被置于零初始化内存中。
它将数组的所有元素一次性初始化为0.Else你可以想象为它们所有人单独做的压力。
“近似”你所做的“非常长”的版本是：
static char vid[25][100]; static firstTime = 1; if(firstTime) { int ii, jj; for(ii = 0; i < 25; ii++) { for (jj = 0; jj < 100; jj++) { vid[ii][jj] = 0; } } firstTime = 0; }
这考虑到这应该只在第一次完成，因为变量被声明为static 。 实际上，正如注释中所指出的， static关键字意味着初始化为零，并映射到称为.bss段的特殊区域。 在main()被调用之前，程序加载器或其他一些机制将其设置为零。 因此，运行的代码看起来并不像上面那样（在大多数处理器上可以非常有效地完成归零内存块，并且不涉及多个维度的循环！）。
但：
初始化是在调用main函数之前发生的事情，而我的“近似等效”代码实际上是在执行期间运行的; 所以，正如Jens指出的那样，事情并非如此。 WhozCraig实际上显示了{0}是简写的显式首次启发; 这是最好的答案。