STL的基本使用之关联容器：map和multiMap的基本使用-优快云博客

STL的基本使用之关联容器：map和multiMap的基本使用

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
头文件 #include< map >
构造函数及析构函数
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
插入删除操作

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;
     }
 }

}