/*請務必運行以下程序后對照閱讀*/  #include <set> #include <iostream> using namespace std;  int main() {   ///1. 初始化   set<int> num;   set<int>::iterator iter;   cout << num.max_size() << endl;///set容納上限   cout << endl;    ///2. 添加元素   for (int i = 0; i < 10; i++)     num.insert(i);   cout << num.size() << endl;   cout << endl;    ///3. 遍歷   ///不同于map，set容器不提供下標操作符   for (iter = num.begin(); iter != num.end(); iter++)     cout << *iter << " " ;   cout << endl;   cout << endl;    ///4. 查詢   iter = num.find(1);   if (iter != num.end())     cout << *iter << endl;   else     cout << -1 << endl;   iter = num.find(99);   if (iter != num.end())     cout << *iter << endl;   else     cout << -1 << endl;   cout << endl;    ///5. 刪除   iter = num.find(1);   num.erase(iter);   cout << num.size() << endl;   for (iter = num.begin(); iter != num.end(); iter++)     cout << *iter << " " ;   cout << endl;   cout << endl;    ///6. 判空與清空   if (!num.empty())     num.clear(); }