c++的map中遍历

C++中的map可以使用迭代器进行遍历，以下是两种常见的遍历方式：

1.正向遍历

#include <map>
#include <iostream>
using namespace std;

int main() {
    map<int, string> ss;
    ss[0] = "nihao";
    ss[1] = "hello";
    ss[2] = "cpp";
    map<int, string>::iterator it;
    for (it = ss.begin(); it != ss.end(); it++) {
        cout << it->first << " " << it->second << endl;
    }
    return 0;
}

输出：

0 nihao
1 hello
2 cpp

2.反向遍历

#include <map>
#include <string>
#include <iostream>
using namespace std;

int main() {
    map<int, string> mapStudent;
    mapStudent[1] = "student_one";
    mapStudent[2] = "student_two";
    mapStudent[3] = "student_three";
    map<int, string>::reverse_iterator iter;
    for (iter = mapStudent.rbegin(); iter != mapStudent.rend(); iter++) {
        cout << iter->first << " " << iter->second << endl;
    }
    return 0;
}

输出：

3 student_three
2 student_two
1 student_one