std :: pair和std :: tuple之间的区别只有两个成员？ [英] Difference between std::pair and std::tuple with only two members?

问题描述

只有两个成员的 std :: pair 和 std :: tuple 之间有区别吗？ （除了明显的 std :: pair 需要两个且只有两个成员，而 tuple 可能有更少...）

Is there a difference between an std::pair and an std::tuple with only two members? (Besides the obvious that std::pair requires two and only two members and tuple may have less...)

推荐答案

有一些区别：

1. std :: tuple 永远不会被标准布局（至少，不是按标准）。如果 T 和都是标准布局，则每个 std :: pair< T，Y&

1. std::tuple can never be be standard-layout (at least, it's not required to be by the standard). Every std::pair<T, Y> is standard-layout if both T and Y are standard-layout.

获得对的内容会更容易一些 code>比 tuple 。您必须在 tuple 案例中使用函数调用，而对案例只是一个成员字段。 p>


It's a bit easier to get the contents of a pair than a tuple. You have to use a function call in the tuple case, while the pair case is just a member field.

但是就是这样。

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