朋友今天出了一道题
int main(void)
{
}
问i的值是多少，我想当然的问答是6。但实际运算结果是5，思考下第一反应应该是sizeof是编译时求值导致的。
先看下汇编结果：
.LC0:
main:
.LFB0:
.LFE0:
看下标记1，实际上直接求出了i对应的数据类型值
这个应该是C标准规定的：
6.5.3.4 The sizeof operator
The sizeof operator yields the size (in bytes) of its operand, which may be an
expression or the parenthesized name of a type. The size is determined from the type of
the operand. The result is an integer. If the type of the operand is a variable length array
type, the operand is evaluated; otherwise, the operand is not evaluated and the result is an
integer constant
其中明确说明了sizeof在非可变长度的数组情况下操作数是不会被求值的
文章来源: sizeof(i++)