c++ map和multimap的使用

#include <iostream>
#include <time.h>
#include <map>
#include <vector>

using namespace std;

class PersonItem {
    friend void printMapPerson(map<int, PersonItem> &m);
private:
    int num;
    string name;
    float score;
public:
    PersonItem(){}
    PersonItem(int num, string name, float score) {
        this->num = num;
        this->name = name;
        this->score = score;
    }
};

void printMapPerson(map<int, PersonItem> &m) {
    map<int, PersonItem>::const_iterator it = m.begin();
    for (;  it != m.end() ; it++) {
        cout << "key: " << (*it).first << " ==> " << (*it).second.num << " - "
                << (*it).second.name << " - " << (*it).second.score << endl;
    }
}

void test01() {
    map<int, PersonItem> m;
    // 方式一写入方式
    m.insert(pair<int, PersonItem>(103, PersonItem(103, "luck", 99.9f)));

    //方式二写入方式(推荐)
    m.insert(make_pair(101, PersonItem(101, "job", 77.7f)));

    // 方式三写入方式
    m.insert(map<int, PersonItem>::value_type(102, PersonItem(102, "tom", 666.4f)));

    // 方式四. 这种方式不推荐，不会检查key是否存在，容易越界。
    m[104] = PersonItem(104, "jack", 33.3f);

    printMapPerson(m);

    cout << "test01 end ..." << endl;
}

class Employee {
    friend void employeeJoinDepartment(vector<Employee> &v, multimap<int, Employee> &m);
    friend void showDepartEmployee(multimap<int, Employee> &m);
private:
    string name;
    int age;
    int money;
    string tel;
public:
    Employee(){}
    Employee(string name, int age, int money, string tel) {
        this->name = name;
        this->age = age;
        this->money = money;
        this->tel = tel;
    }
};

void createVectorEmployee(vector<Employee> &v) {
    int i;
    string seedName = "ABCDE";
    srand(time(NULL)); // 随机数设置随机种子.
    for(i=0; i<5; i++) {
        string tmpName = "员工";
        tmpName += seedName[i];
        int age = 20 + i;
        int money = 15000 + rand() % 10 * 1000;
        string tel = to_string(rand());
        v.push_back(Employee(tmpName, age, money, tel));
    }
}

// 员工加入部分函数.
void employeeJoinDepartment(vector<Employee> &v, multimap<int, Employee> &m) {
    vector<Employee>::iterator it = v.begin();
    for(; it != v.end(); it++) {
        cout << "请输入 【" << (*it).name << "】 要加入的部门, 0(销售)、1(研发)、2(财务): ";
        int op = 0;
        cin >> op;
        m.insert(make_pair(op, *it));
    }
}

// 显示部门员工.
void showDepartEmployee(multimap<int, Employee> &m) {

    cout << "请输入要显示的部门, 0(销售)、1(研发)、2(财务)" << endl;
    int op = 0;
    cin >> op;
    switch (op) {
        case 0:
            cout << "--------销售部门员工如下-----------" << endl;
            break;
        case 1:
            cout << "--------研发部门员工如下-----------" << endl;
            break;
        case 2:
            cout << "--------财务部门员工如下-----------" << endl;
            break;
    }
    // 寻找op的位置
    multimap<int, Employee>::iterator ret;
    ret = m.find(op);
    if (ret == m.end()) {
        return;
    }
    // 统计op的数量
    int count = m.count(op);

    // 从op的位置逐个遍历
    for (int i = 0; i < count; i++, ret++) {
        cout << "name: " << (*ret).second.name
            << " money: " << (*ret).second.money
            << " tel: " << (*ret).second.tel
            << " age: " << (*ret).second.age << endl;
    }

}

void test02() {
    // 创建5个员工 存放到vector
    vector<Employee> v;
    createVectorEmployee(v);

    // 5个员工加入部门
    multimap<int, Employee> m;
    employeeJoinDepartment(v, m);

    // 显示部门员工
    showDepartEmployee(m);

    cout << "test02 end ..." << endl;
}

int main() {
    test01();
    test02();
    return 0;
}