c - C 中数组初始化中的方括号是什么意思？

Question

static uint8_t togglecode[256] = {
    [0x3A] CAPSLOCK,
    [0x45] NUMLOCK,
    [0x46] SCROLLLOCK
};

这里的[0x3A]是什么意思？我只学过像 int a[2] = {1, 2};

这样的语句

Answer 1

这意味着初始化数组的第n个元素。您给出的示例意味着:

togglecode[0x3A] == CAPSLOCK
togglecode[0x45] == NUMLOCK
togglecode[0x46] == SCROLLLOCK

这些被称为 "designated initializers" ，实际上是 C99 标准的一部分。但是，没有 = 的语法则不然。从该页面:

An alternative syntax for this which has been obsolete since GCC 2.5 but GCC still accepts is to write [index] before the element value, with no =.