18.7 SortContactsList.cpp

#include <list>
#include <string>
#include <iostream>
using namespace std;

template <typename T>
void displayAsContents(const T& container)
{
   for(auto element = container.cbegin();
         element != container.cend();
         ++ element )
     cout << *element << endl;

   cout << endl;
}

struct ContactItem
{
   string name;
   string phone;
   string displayAs;

   ContactItem(const string& conName, const string & conNum)
   {
      name = conName;
      phone = conNum;
      displayAs =(name + ": " + phone);
   }

   // used by list::remove() given contact list item
   bool operator ==(const ContactItem& itemToCompare) const
   {
      return(itemToCompare.name == this->name);
   }

   // used by list::sort() without parameters
   bool operator < (const ContactItem& itemToCompare) const
   {
      return(this->name < itemToCompare.name);
   }

   // Used by displayAsContents via cout
   operator const char*() const
   {
     return displayAs.c_str();
   }
};

bool SortOnphoneNumber(const ContactItem& item1,
                           const ContactItem& item2)
{
   return(item1.phone < item2.phone);
}

int main()
{
   list <ContactItem> contacts;
   contacts.push_back(ContactItem("Oprah Winfrey", "+1 7889 879 879"));
   contacts.push_back(ContactItem("Bill Gates", "+1 97 7897 8799 8"));
   contacts.push_back(ContactItem("Angi Merkel", "+49 23456 5466"));
   contacts.push_back(ContactItem("Vlad Putin", "+7 6645 4564 797"));
   contacts.push_back(ContactItem("John Travolta", "91 234 4564 789"));
   contacts.push_back(ContactItem("Angelina Jolie", "+1 745 641 314"));

   cout << "List in initial order: " << endl;
   displayAsContents(contacts);

   contacts.sort();
   cout << "Sorting in alphabetical order via operator<:" << endl;
   displayAsContents(contacts);

   contacts.sort(SortOnphoneNumber);
   cout << "Sorting in order of phone numbers via predicate:" << endl;
   displayAsContents(contacts);

   cout << "After erasing Putin from the list: " << endl;
   contacts.remove(ContactItem("Vlad Putin", ""));
   displayAsContents(contacts);

   return 0;
}