1 #include <iostream>

 2 #include <map>

 3

 4 using namespace std;

 5

 6 int main()

 7 {

 8     map<int, string> mapStu1;

 9     mapStu1.insert(pair<int, string>(1, "内容A"));

10     mapStu1.insert(pair<int, string>(2, "内容B"));

11     mapStu1.insert(pair<int, string>(3, "内容C"));

12

13     if (!mapStu1.empty())

14     {

15         cout << "容器 mapStu1 中共有" << mapStu1.size() << "个元素" << endl;

16     }

17     else

18     {

19         cout << "容器 mapStu1 中共有" << mapStu1.size() << "个元素, " << "容器为空" << endl;

20     }

21

22     cout << "删除所有元素" << endl;

23     mapStu1.clear();

24     if (!mapStu1.empty())

25     {

26         cout << "容器 mapStu1 中共有" << mapStu1.size() << "个元素" << endl;

27     }

28     else

29     {

30         cout << "容器 mapStu1 中共有" << mapStu1.size() << "个元素, " << "容器为空" << endl;

31     }

32

33     return 0;

34 }

 1 #include <iostream>

 2 #include <map>

 3

 4 using namespace std;

 5

 6 int main()

 7 {

 8     map<int, string> mapStu1;

 9

10     mapStu1.insert(pair<int, string>(1, "内容A"));

11     mapStu1.insert(pair<int, string>(2, "内容B"));

12     mapStu1.insert(pair<int, string>(3, "内容C"));

13     mapStu1.insert(pair<int, string>(4, "内容D"));

14

15     map<int, string>::iterator it1 = mapStu1.begin();

16     cout << "删除首元素前, 首元素为:" << it1->first << "首元素内容为: " << it1->second << endl;

17     cout << endl;

18     map<int, string>::iterator it2 = mapStu1.erase(mapStu1.begin());

19     cout << "删除首元素后, 新的首元素为:" << it2->first << "首元素内容为: " << it2->second << endl;

20

21     return 0;

22 }

 1 #include <iostream>

 2 #include <map>

 3

 4 using namespace std;

 5

 6 int main()

 7 {

 8     map<int, string> mapStu1;

 9

10     mapStu1.insert(pair<int, string>(1, "内容A"));

11     mapStu1.insert(pair<int, string>(2, "内容B"));

12     mapStu1.insert(pair<int, string>(3, "内容C"));

13     mapStu1.insert(pair<int, string>(4, "内容D"));

14     mapStu1.insert(pair<int, string>(5, "内容E"));

15

16     cout << "遍历mapStu1: " << endl;

17     for (map<int, string>::iterator it = mapStu1.begin(); it != mapStu1.end(); it++)

18     {

19         cout << "容器 mapStu1 的第" << it->first << "个元素为: " << it->second << endl;

20     }

21

22     cout << endl << "删除除首元素与尾部元素之间的所有元素" << endl;

23

24     map<int, string>::iterator it = mapStu1.erase(++mapStu1.begin(), --mapStu1.end());

25     cout << endl << "删除完后返回的迭代器所指向的 key 为: " << it->first << "内容为: " << it->second << endl;

26

27     cout << endl << "删除后遍历mapStu1: " << endl;

28     for (map<int, string>::iterator it = mapStu1.begin(); it != mapStu1.end(); it++)

29     {

30         cout << "容器 mapStu1 的第" << it->first << "个元素为: " << it->second << endl;

31     }

32

33     return 0;

34 }

 1 #include <iostream>

 2 #include <map>

 3

 4 using namespace std;

 5

 6 int main()

 7 {

 8     multimap<int, string> multimapStu1;

 9

10     multimapStu1.insert(pair<int, string>(1, "内容A"));

11     multimapStu1.insert(pair<int, string>(1, "内容AA"));

12     multimapStu1.insert(pair<int, string>(1, "内容AAA"));

13     multimapStu1.insert(pair<int, string>(2, "内容B"));

14     multimapStu1.insert(pair<int, string>(3, "内容C"));

15

16     cout << "遍历mapStu1: " << endl;

17     for (map<int, string>::iterator it = multimapStu1.begin(); it != multimapStu1.end(); it++)

18     {

19         cout << "容器 mapStu1 key 为" << it->first << "的个元素为: " << it->second << endl;

20     }

21     cout << endl << "删除所有 key 为 1 的组" << endl;

22

23     cout << endl << "共删除了" << multimapStu1.erase(1) << "个 key 为1的组" << endl;            //会返回删除的个数

24     cout << "遍历mapStu1: " << endl;

25     for (map<int, string>::iterator it = multimapStu1.begin(); it != multimapStu1.end(); it++)

26     {

27         cout << "容器 mapStu1 key 为" << it->first << "的个元素为: " << it->second << endl;

28     }

29

30     return 0;

31 }