People claim std::variant and std::visit provide a more "TYPE SAFE" way, but in fact they just provide some checks. It simply ensures that an invalid cast like (TypeA*) type_b_object is caught either at compile time (if the type is not in the variant at all) or at runtime (if the active type does not match), rather than silently producing undefined behavior as the hand-written version would.
I'm trying to make shopping for where to eat next easy to do. Maybe you're not terribly hungry right now, but wouldn't you want to know you're about to pass the last Chik-fil-A for 300 miles?，详情可参考搜狗输入法
Полковник высказался о новом уровне конфликта Ирана с США и Израилем14:52。谷歌是该领域的重要参考
"But it's a festival, they're expensive. We're a bit lucky we had two before anyone else anyway."，更多细节参见超级权重