Preliminaries

Throughout this chapter we'll focus on using objects as elements of containers. Instead of demonstrating the different containers and algorithms (etc.) using primitive data types, we'll instead use a simple C++ class (although, initially with vector, we'll begin with primitive data types).

The examples will revolve around using an address class - albeit very simple (and unrealistic!). Here's the header file, Address.hh:

     /* Address.hh */
     #ifndef Address_hh
     #define Address_hh
     
     #include <string>
     
     class Address
     {
     public:
       Address(){name=street=city=""; phone=0;}
       Address(string n, string s, string c, long p);
       void print() const;
       bool operator < (const Address& addr) const;
       bool operator == (const Address& addr) const;
       string getName() const {return name;}
       string getStreet() const {return street;}
       string getCity() const {return city;}
       long getPhone() const {return phone;}
     private:
       string name;
       string street;
       string city;
       long phone;
     };
     
     #endif
     

     Example 3.1: Address.hh
     

... and the definition, Address.cc:

     /* Address.cc */
     #include "Address.hh"
     
     Address::Address(string n, string s, string c, long p)
     {
       name = n;
       street = s;
       city = c;
       phone = p;
     };
     void Address::print() const
     {
       cout <<
         "Name: " << name << ", " <<
         "Street: " << street << ", " <<
         "City: " << city << ", " <<
         "Phone: " << phone << endl;
     };
     bool Address::operator < (const Address& addr) const
     {
       if (name < addr.getName())
         return true;
       else
         return false;
     };
     bool Address::operator == (const Address& addr) const
     {
       if (name == addr.getName())
         return true;
       else
         return false;
     };
     

     Example 3.2: Address.cc
     

We've added operators because they'll be useful later when we come to sort the elements using different containers. The equality operators are not very strict; we're only interested in comparing names, and consider that two people with the same name to the same person; this isn't really important, given the limited nature of the examples to follow.

In addition, we'll be using a header file to keep a number of different Address objects in:

     /* AddressRepository.hh */
     #ifndef Address_Repoditory_hh
     #define Address_Repoditory_hh
     
     #include "Address.hh"
     
     Address addr1("Jane", "12 Small St.", "Worcs", 225343);
     Address addr2("Edith", "91 Glib Terrace", "Shrops", 858976);
     Address addr3("Adam", "23 Big St.", "Worcs", 443098);
     Address addr4("Jane", "55 Almond Terrace", "Worcs", 242783);
     Address addr5("Bob", "2 St. Annes Walk", "Oxford", 303022);
     
     #endif
     

     Example 3.3: AddressRepository.hh