1. Map & multimap 的拷贝构造与赋值
map(const map &mp); //拷贝构造函数
map& operator=(const map &mp); //重载等号操作符
map.swap(mp); //交换两个集合容器
拷贝构造代码示例:
1 #include <iostream>
2 #include <map>
3
4 using namespace std;
5
6 int main()
7 {
8 map<int, string> mapStu1; //默认为升序,与 map<int, string, less<int>> mapStu1; 同效
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>mapStu2(mapStu1); //拷贝构造,此时 mapStu2 与 mapStu1 中元素一致
16
17 for (map<int, string>::iterator it = mapStu1.begin(); it != mapStu1.end(); it++) //mapStu1的遍历
18 {
19 cout << "mapStu1的第 " << it->first << "个参数为: " << it->second <<endl;
20 }
21 cout << endl;
22 for (map<int, string>::iterator it = mapStu2.begin(); it != mapStu2.end(); it++) //mapStu2的遍历
23 {
24 cout << "mapStu2的第 " << it->first << "个参数为: " << it->second << endl;
25 }
26
27 return 0;
28 }
打印结果:
重载等号操作代码示例:
1 #include <iostream>
2 #include <map>
3
4 using namespace std;
5
6 int main()
7 {
8 map<int, string> mapStu1; //默认为升序,与 map<int, string, less<int>> mapStu1; 同效
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>mapStu2;
16 /*
17 源代码已经实现等号重载,可以直接使用等号赋值
18 map& operator=(const map& _Right){
19 _Mybase::operator=(_Right);
20 return *this;
21 }
22 */
23 mapStu2 = mapStu1;
24
25 for (map<int, string>::iterator it = mapStu1.begin(); it != mapStu1.end(); it++) //mapStu1的遍历
26 {
27 cout << "mapStu1的第 " << it->first << "个参数为: " << it->second <<endl;
28 }
29 cout << endl;
30 for (map<int, string>::iterator it = mapStu2.begin(); it != mapStu2.end(); it++) //mapStu2的遍历
31 {
32 cout << "mapStu2的第 " << it->first << "个参数为: " << it->second << endl;
33 }
34
35 return 0;
36 }
打印结果:
交换容器内容代码示例:
1 #include <iostream>
2 #include <map>
3
4 using namespace std;
5
6 int main()
7 {
8 map<int, string> mapStu1;
9 map<int, string> mapStu2;
10
11 mapStu1.insert(pair<int, string>(1, "内容A"));
12 mapStu1.insert(pair<int, string>(2, "内容B"));
13 mapStu1.insert(pair<int, string>(3, "内容C"));
14 mapStu1.insert(pair<int, string>(4, "内容D"));
15
16 mapStu2.insert(pair<int, string>(5, "内容E"));
17 mapStu2.insert(pair<int, string>(6, "内容F"));
18 mapStu2.insert(pair<int, string>(7, "内容G"));
19 mapStu2.insert(pair<int, string>(8, "内容H"));
20
21 cout << "交换前打印:" << endl;
22 for (map<int, string>::iterator it = mapStu1.begin(); it != mapStu1.end(); it++) //mapStu1的遍历
23 {
24 cout << "mapStu1的第 " << it->first << "个参数为: " << it->second <<endl;
25 }
26 cout << endl;
27 for (map<int, string>::iterator it = mapStu2.begin(); it != mapStu2.end(); it++) //mapStu2的遍历
28 {
29 cout << "mapStu2的第 " << it->first << "个参数为: " << it->second << endl;
30 }
31
32 mapStu1.swap(mapStu2);
33 cout << endl << "交换后打印:" << endl;
34 for (map<int, string>::iterator it = mapStu1.begin(); it != mapStu1.end(); it++) //mapStu1的遍历
35 {
36 cout << "mapStu1的第 " << it->first << "个参数为: " << it->second << endl;
37 }
38 cout << endl;
39 for (map<int, string>::iterator it = mapStu2.begin(); it != mapStu2.end(); it++) //mapStu2的遍历
40 {
41 cout << "mapStu2的第 " << it->first << "个参数为: " << it->second << endl;
42 }
43
44 return 0;
45 }
打印结果:
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