C++ Map 遍历方法

int main(){
    map<int, int> m;
    for (int i = 0; i < 10; i++){
        m[i] = i*10;
    }
    map<int,int>::iterator iter;
    iter = m.begin();
    while(iter != m.end()){
        cout << iter->first << "-" << iter->second << endl;
        iter++;
    }
    for (iter = m.begin();iter != m.end(); iter++){
        cout << iter->first << "-" << iter->second << endl;
    }
    for(auto &it : m){
        cout << it.first << "-" << it.second <<endl;
    }
    //反向遍历，只举一个例子
    iter = m.end();
    iter--;
    while(iter != m.begin()){
        cout << iter->first << "-" << iter->second << endl;
        iter--;
    }
    return 0;
}