C++第10课 STL容器 （九）

1.map(映射)

/*
    map：映射,一种对应关系
    自带排序（按照键去排序）
    键唯一，相同键采用最后一次插入的数据，覆盖的方式去处理
    存储的数据是: 数对类型(pair)
*/
void testMap()
{
    map<int, string>str;
    //1.pair对象插入
    str.insert(pair<int, string>(1, "小可爱"));
    //2.数组法插入
    str[-1] = "小甜心";
    //3.间接通过make_pair构建一个pair类型
    str.insert(make_pair<int, string>(2, "小宝贝"));
    str[-1] = "小美女";
    for (auto v : str) {
        cout << v.first << "\t" << v.second << "\t";
    }
    cout << endl;

    map<int,string>::iterator iter=str.begin();
    while (iter != str.end()) {
        cout << (*iter).first << "\t" << (*iter).second << "\t";
        iter++;
    }
    cout << endl;
}
class MM
{
public:
    MM() = default;
    MM(string name, int age) :name(name), age(age) {}
    string getName() { return name; }
    int getAge() { return age; }
    bool operator<(const MM& object) const
    {
        return this->age < object.age;
    }
    friend ostream& operator<<(ostream& out, const MM& mm)
    {
        out << mm.name << "\t" << mm.age;
        return out;
    }
protected:
    string name;
    int age;
};
class GG
{
public:
    GG() = default;
    GG(string name, int age) :name(name), age(age) {}
    string getName() { return name; }
    int getAge() { return age; }
    friend ostream& operator<<(ostream& out, const GG& gg)
    {
        out << gg.name << "\t" << gg.age;
        return out;
    }
protected:
    string name;
    int age;
};
template <class _Ty1, class _Ty2>
void print(map<_Ty1, _Ty2>& temp)
{
    for (auto v : temp)
    {
        //int                        MM
        cout << v.first << "\t" << v.second << endl;
    }
}
void testUserData()
{
    //可以任意对应
    map<int, MM> mmData;
    mmData[1] = MM("小美人", 18);
    mmData[3] = MM("小可爱", 29);
    mmData[2] = MM("小甜心", 28);
    print(mmData);
    map<MM, GG> mmgg;   //less<int> <
    mmgg[MM("张三", 18)] = GG("李四", 20);
    mmgg[MM("王五", 29)] = GG("赵六", 34);
    mmgg[MM("美女", 45)] = GG("帅哥", 55);
    cout << mmgg[MM("美女", 45)].getName() << mmgg[MM("美女", 45)].getAge() << endl;
    print(mmgg);
    //<
    map<string, string, less<string>>  strData; //和默认是一样，从小到大
    //>
    map<string, string, greater<string>> greaterData;    //从大到小

}
void testmultimap()
{

    multimap<int, string> mulData;
    //注意点： 多重映射不能采用下标法赋值
    mulData.insert(make_pair<int, string>(3, "测试结果"));
    mulData.insert(pair<int, string>(1, "多重映射"));
    mulData.insert(make_pair<int, string>(1, "多重映射2"));
    for (auto v : mulData)
    {
        cout << v.first << "\t" << v.second << endl;
    }
}
void testNestMap()
{
    map<int, map<string, MM>>  mapData;
    map <string, MM> mmData;
    mmData["美女"] = MM("小美", 18);
    mapData[0] = mmData;
    cout << mapData[0]["美女"].getName() << mapData[0]["美女"].getAge() << endl;
}