3.删除

//删除
/*
int main()
{set<int> s;s.insert({ 2,4,5,2,6,8,10,15 });for (auto e : s){cout << e << " ";}cout << endl;//删除最小的元素就删除排序后的首元素s.erase(s.begin());for (auto e : s){cout << e << " ";}cout << endl;//指定删除元素并判断是否删除成功//可以使用erase的返回值统计待删除元素出现的次数来判断是否删除成功int x = 0;cout << "输入你要删除的元素:";cin >> x;int num = s.erase(x);if (num){cout << "删除成功" << endl;for (auto e : s){cout << e << " ";}cout << endl;}else{cout << "删除失败" << endl;for (auto e : s){cout << e << " ";}cout << endl;}//使用迭代器删除//如果未查找到则直接返回迭代器尾部auto pos = s.find(x);if (pos != s.end()){s.erase(x);cout << "删除成功" << endl;for (auto e : s){cout <