考虑以下初始化:
/* C, C++ */
int a[] = { f(), g() };
struct { int x, y } foo = { f(), g() };
/* C++ */
struct goo { goo(int x, int y); };
goo b = { f(), g() };
goo c { f(), g() }; /* C++11 */
goo d ( f(), g() );
f() 和 g() 的执行顺序是否在 C 和 C++ 标准规定的任何行中？
最佳答案
在这两种情况下
goo b = { f(), g() };
goo c { f(), g() }; /* C++11 */
评估顺序是从左到右确定的，所有副作用都应在下一个初始化程序之前应用。
来自 C++ 标准
4 Within the initializer-list of a braced-init-list, the initializer-clauses, including any that result from pack expansions (14.5.3), are evaluated in the order in which they appear. That is, every value computation and side effect associated with a given initializer-clause is sequenced before every value computation and side effect associated with any initializer-clause that follows it in the comma-separated list of the initializer-list.
但是在 C 中还有其他规则
The evaluations of the initialization list expressions are indeterminately sequenced with respect to one another and thus the order in which any side effects occur is unspecified.
关于c++ - 在 C、C++ 中的初始化中排序，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22515685/