d_state.h

这是数据结构和算法的国外经典书籍.清华大学出版社出版的<数据结构C++语言描述-应用模板库STL>陈君 译 英文名称是Data Structures with C++ Using STL.

#ifndef STATECITY_CLASS
#define STATECITY_CLASS

#include <iostream>
#include <string>

using namespace std;

// object stores the state name and city in the state
class stateCity
{
	public:
		stateCity (const string& name = "", const string& city = ""):
			stateName(name), cityName(city)
		{}

		// output the state and city name in the format
		//    cityName, stateName
		friend ostream& operator<< (ostream& ostr, const stateCity& state)
		{
			ostr << state.cityName << ", " << state.stateName;

			return ostr;
		}

		// operators < and == must be defined to use with set object.
		// operators use only the stateName as the key
		friend bool operator< (const stateCity& a, const stateCity& b)
		{
			return a.stateName < b.stateName;
		}

		friend bool operator== (const stateCity& a, const stateCity& b)
		{
			return a.stateName == b.stateName;
		}

	private:
		string stateName, cityName;
};

#endif	// STATECITY_CLASS