map容器

---

#include

void test1()

{

    map k;

    //插入值

    //4种方式

    //1.

    k.insert(pair(1, 10));

    //2.

    k.insert(make_pair(2, 20));

    //3. 

    k.insert(map::value_type(3, 30));

    //4.

    k[4] = 10;

    for(map::iterator it = k.begin(); it != k.end(); it++)

    {

        cout << it -> first << endl;

        cout << it -> second << endl;

    }

    cout << k[5] << endl;

        for(map::iterator it = k.begin(); it != k.end(); it++)

    {

        cout << it -> first << endl;

        cout << it -> second << endl;

    }

    cout << k[4] << endl;

    if(k.empty())

    {

        cout << "空" << endl;

    }

    else

    {

        cout << "seze： " << k.size() << endl;

    }

}

void test2()

{

        map k;

    //插入值

    //4种方式

    //1.

    k.insert(pair(1, 10));

    //2.

    k.insert(make_pair(2, 20));

    //3. 

    k.insert(map::value_type(3, 30));

    //4.

    k[4] = 10;

    k.erase(1);

    for(map::iterator it = k.begin(); it != k.end(); it++)

    {

        cout << it -> first << endl;

        cout << it -> second << endl;

    }

    map::iterator pos = k.find(2);

    if(pos != k.end())

    {

        cout << "key： " << pos -> first << "  value： " << pos -> second << endl;

    }

    else

    cout << "未找到" << endl;

    int num = k.count(2);

    cout << "num = " << num << endl; //只能为0 / 1

    map::iterator ret = k.lower_bound(2); //>=

    if(ret != k.end())

    {

    cout << ret -> first << endl;

    cout << ret -> second << endl;

    }

    else

    cout << "NULL" << endl;

    map::iterator ret2 = k.upper_bound(2); //>

    if(ret != k.end())

    {

    cout << ret2 -> first << endl;

    cout << ret2 -> second << endl;

    }

    else

    cout << "NULL" << endl;

    pair::iterator ,map::iterator> ret3 = k.equal_range(3);

    if(ret3.first != k.end())

    {

        cout << "找到了lower_bound key ： " << ret3.first -> first << endl;

        cout << "  value : " << ret3.first -> second << endl;

    }

    else

    {

        cout << "未找到" << endl;

    }   

    if(ret3.second != k.end())

    {

        cout << "找到了lower_bound key ： " << ret3.second -> first << endl;

        cout << "  value : " << ret3.second -> second << endl;

    }

    else

    {

        cout << "未找到" << endl;

    } 

}

//-------------------

class mycompare

{

    public:

    bool operator()(int v1, int v2)

    {

        return v1 > v2;

    }

};

void test3()

{

    map k;

    //1.

    k.insert(pair(1, 10));

    //2.

    k.insert(make_pair(2, 20));

    //3. 

    k.insert(map::value_type(3, 30));

    //4.

    k[4] = 10;

    //从大到小

    for(map::iterator it = k.begin(); it != k.end(); it++)

    {

        cout << "key： " << it -> first << "  valuse： " << it -> second << endl;

    }

}