STL的基本使用之关联容器：map和multiMap的基本使用

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

   include

   include

   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<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