std::set交集

std::set没有内置的交集操作。但是可以通过迭代器遍历两个set，并找出共同的元素来实现交集操作。下面是一个示例代码，演示了如何找到两个std::set的交集元素：

#include <iostream>
#include <set>

int main() {
    std::set<int> set1 = {1, 2, 3, 4, 5};
    std::set<int> set2 = {4, 5, 6, 7, 8};

    std::set<int> intersection;

    for (auto it = set1.begin(); it != set1.end(); ++it) {
        if (set2.find(*it) != set2.end()) {
            intersection.insert(*it);
        }
    }

    std::cout << "Intersection of set1 and set2: ";
    for (auto it = intersection.begin(); it != intersection.end(); ++it) {
        std::cout << *it << " ";
    }
    std::cout << std::endl;

    return 0;
}

这段代码首先创建了两个std::set对象set1和set2，然后通过遍历set1中的元素，并在set2中查找是否存在相同的元素。如果存在，将该元素插入到intersection set中。最后，遍历intersection set并打印出交集的元素。可以输出：Intersection of set1 and set2: 4 5 。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
#### 引用[.reference_title]
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