STL的基本使用之关联容器：map和multiMap的基本使用

1. 简介

   • map 和 multimap 内部也都是使用红黑树来实现，他们存储的是键值对，并且会自动将元素的key进行排序。两者不同在于map 不允许key重复，而multiSet 允许key重复

2. 头文件 #include< map >

3. 构造函数及析构函数

4. 非变动性操作函数

   • 运算符重载
   • 下标运算符
   • 查找操作函数
   • 赋值操作
   • 迭代器操作

5. 插入删除操作

6. 范例如下

    #include <iostream>
   
    #include <map>
   
    #include <iomanip>
   
    using namespace std;
   
    int main ()
   
    {
   
    #pragma mark - 基本使用
   
    map<int,string> c;
   
    c.insert(make_pair(1,"1")); c.insert(make_pair(2,"2"));
   
    c.insert(make_pair(4,"4")); c.insert(make_pair(5,"5"));
   
    c.insert(make_pair(6,"6"));
   
    cout << "lower_bound(3): "  << c.lower_bound(3)->second << endl;
   
    cout << "upper_bound(3): " << c.upper_bound(3)->first << endl;
   
    cout << "equal_range(3): "
   
    << (c.equal_range(3).first)->first << " "
   
    << (c.equal_range(3).second)->first << endl;
   
    cout << endl;
   
    cout << "lower_bound(5): "  << c.lower_bound(5)->first << endl;
   
    cout << "upper_bound(5): " << c.upper_bound(5)->first << endl;
   
    cout << "equal_range(5): "
   
    << (c.equal_range(5).first)->first << " "
   
    << (c.equal_range(5).second)->first << endl;
   
    c.insert(c.lower_bound(3), make_pair(3, "3"));
   
    //    c.erase(4);
   
    c.erase(c.find(4));
   
    map<int,string>::iterator i;
   
    for (i = c.begin(); i!=c.end(); i++) {
   
        cout<<i->first<<" ";
   
    }
   
    cout<<endl;
   
    #pragma mark-   实例1：将map当做关联数组
   
    typedef map<string,float> StringFloatMap;
   
    StringFloatMap stocks;      // create empty container
   
    //insert some elements
   
    stocks["BASF"]	= 369.50;
   
    stocks["VW"]	= 413.50;
   
    stocks["Daimler"]	= 819.00;
   
    stocks["BMW"]	= 834.00;
   
    stocks["Siemens"]	= 842.20;
   
    //print all elements
   
    StringFloatMap::iterator pos;
   
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
   
        cout << "stock: " << pos->first << "\t"
   
        << "price: " << pos->second << endl;
   
    }
   
    cout << endl;
   
    //boom (all prices doubled)
   
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
   
        pos->second *= 2;
   
    }
   
    //print all elements
   
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
   
        cout << "stock: " << pos->first << "\t"
   
        << "price: " << pos->second << endl;
   
    }
   
    cout << endl;
   
    /*rename key from "VW" to "Volkswagen"
   
     *-only provided by exchanging element
   
     */
   
    stocks["Volkswagen"] = stocks["VW"];
   
    stocks.erase("VW");
   
    //print all elements
   
    for (pos = stocks.begin(); pos != stocks.end(); ++pos) {
   
        cout << "stock: " << pos->first << "\t"
   
        << "price: " << pos->second << endl;
   
    }
   
    #pragma mark - 实例2：将multimap当做字典
   
    typedef multimap<string,string> StrStrMMap;
   
    //create empty dictionary
   
    StrStrMMap dict;
   
    //insert some elements in random order
   
    dict.insert(make_pair("day","Tag"));
   
    dict.insert(make_pair("strange","fremd"));
   
    dict.insert(make_pair("car","Auto"));
   
    dict.insert(make_pair("smart","elegant"));
   
    dict.insert(make_pair("trait","Merkmal"));
   
    dict.insert(make_pair("strange","seltsam"));
   
    dict.insert(make_pair("smart","raffiniert"));
   
    dict.insert(make_pair("smart","klug"));
   
    dict.insert(make_pair("clever","raffiniert"));
   
    //print all elements
   
    StrStrMMap::iterator pos1;
   
    cout.setf (ios::left, ios::adjustfield);
   
    cout << ' ' << setw(10) << "english "
   
    << "german " << endl;
   
    cout << setfill('-') << setw(20) << ""
   
    << setfill(' ') << endl;
   
    for (pos1 = dict.begin(); pos1 != dict.end(); ++pos1) {
   
        cout << ' ' << setw(10) << pos1->first.c_str()
   
        << pos1->second << endl;
   
    }
   
    cout << endl;
   
    //print all values for key "smart"
   
    string word("smart");
   
    cout << word << ": " << endl;
   
    for (pos1 = dict.lower_bound(word);
   
         pos1 != dict.upper_bound(word); ++pos1) {
   
        cout << " " << pos1->second << endl;
   
    }
   
    //print all keys for value "raffiniert"
   
    word = ("raffiniert");
   
    cout << word << ": " << endl;
   
    for (pos1 = dict.begin(); pos1 != dict.end(); ++pos1) {
   
        if (pos1->second == word) {
   
            cout << " " << pos1->first << endl;
   
        }
   
    }
   

   }

7. 运行截图