问题描述
我有几个关于如何使用C ++集(std :: set)的问题
I have a couple questions about how to use C++ sets (std::set)
-
有没有办法得到两个C ++集合的联合,交集或区别? (写自己的功能很容易,但我想知道是否有内置的功能)
Is there a way to get the union, intersection, or difference of two C++ sets? (It's pretty easy to write my own functionto do that but I wanted to know if there was a built in function for it)
可以将C ++集合用作
Can C++ sets be used as keys in a map?
推荐答案
使用,,和功能。
Use the set_difference()
, set_union()
, set_intersection()
and set_symmetric_difference()
functions.
设置和映射支持可以比较的任何键类型。默认情况下,该类型定义了 operator<()
,但您可以提供自己的比较器。 C ++集没有定义 operator<()
,因此不能用作键,除非您提供自己的比较器。
Sets and maps support any key type that can compare. By default this means the type has operator<()
defined, but you can provide your own comparator. C++ sets don't have operator<()
defined and therefore can't be used as keys unless you provide your own comparator.
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