// Program to demonstrate sorting and searching of personnel records,
// showing how to define a function object that tells how to compare two
// such records.

#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;;

int const LENGTH = 30;

struct Person {
   char firstName[LENGTH];
   char lastName[LENGTH];
   int number;
};

//--------------------------  output  ----------------------------------------
void output(const Person& record) {
   cout << record.firstName << " " << record.lastName 
        << ", Record No. " << record.number << endl;
}

//--------------------------  readNames  ------------------------------------
void readNames(vector<Person>& roster) {
   Person thePerson;
   int recNum = 1;                      
   for (;;) {
      cout << "Enter first name (--- to stop):  ";
      cin >> thePerson.firstName;
      if (strcmp(thePerson.firstName, "---") == 0) 
            break;
      cout << "Enter last name:  ";
      cin >> thePerson.lastName;
      thePerson.number = recNum++;
      roster.push_back(thePerson);           // put thePerson at end of roster
   }
}

//---------------------------  operator()  -----------------------------------
// Following is a function object type, 
// defines how to compare persons (for sorting/searching)
struct NameCompare {  
   bool operator()(const Person& a, const Person& b) const {
      return strcmp(a.lastName, b.lastName) < 0;  // based on last names only
   }
};

//-----------------------------  main  ---------------------------------------
int main() {
   // a comparison function object, used for sorting and searching
   NameCompare nameComp;  

   // fill and sort a vector of Persons
   vector<Person> roster;
   readNames(roster);
   sort(roster.begin(), roster.end(), nameComp);

   // display the list alphabetically
   cout << "Current persons, listed alphabetically by last name:" << endl;
   vector<Person>::iterator i;
   for (i = roster.begin(); i != roster.end(); ++i) 
      output(*i);
   cout << endl << endl;

   // search for desired persons by last name, "---" terminates
   Person searchRecord;
   for (;;) {
      cout << "Enter last name to search for (--- to stop):  ";
      cin >> searchRecord.lastName;
      if (strcmp(searchRecord.lastName, "---") == 0) 
         break;

      cout << "Searching for a person named " 
           << searchRecord.lastName << "..." << endl;
      i = lower_bound(roster.begin(), roster.end(), searchRecord, nameComp);

      if (strcmp((*i).lastName, searchRecord.lastName) == 0) {
         cout << "Found ";
         output(*i);
         cout << endl;
      }
      else
         cout << "Sorry, there's no record of a person named "
              << searchRecord.lastName << endl << endl;
   }
   return 0;
}