#include <iostream.h>
#include <fstream.h>
#include "apvector.h"

const int MAX_BOXES = 100;

struct MailInfo
{
    int POBox;         
    int mailCount;              // # pieces of mail for this po box
};


class MailBoxes
{
  public:
    MailBoxes();     // initial capacity = MAX_BOXES, zero boxes stored

    void processMail(istream & input);   // process file of po boxes
    void printAll(ostream & output);
    
  private:
    
    int boxIndex(int box);          // helper function, returns index
    
    apvector<MailInfo> myBoxes;     // list of all poboxes and counts
    int                myBoxCount;  // # of itmes stored in myBoxes
};


MailBoxes::MailBoxes()
    : myBoxes(MAX_BOXES),
      myBoxCount(0)
// postcondition: capacity = MAX_BOXES, zero boxes stored    
{
    
}

int MailBoxes::boxIndex(int box)
//postcondition: returns the index of the element in myBoxes
//               whose POBox field equals box if there is such an element;
//               otherwise, returns -1.
{
    int k;
    for(k=0; k < myBoxCount; k++)
    {
	if (myBoxes[k].POBox == box)
	{
	    return k;
	}
    }
    return -1;
}

void MailBoxes::processMail(istream & input)
// precondition:  input is formatted correctly, is open for reading,
//                 and is positioned at the beginning of the file;
//                 the file contains no more than MAX_BOXES different
//                 P.O. box numbers    
{
    int box;
    while (input >> box)
    {
	int index = boxIndex(box);
	if (index != -1)
	{
	    myBoxes[index].mailCount++;
	}
	else
	{
	    myBoxes[myBoxCount].POBox = box;
	    myBoxes[myBoxCount].mailCount = 1;
	    myBoxCount++;
	}	
    }
}


void MailBoxes::printAll(ostream & output)
{
    int k;
    for(k=0; k < myBoxCount; k++)
    {
	output << "box = [" << myBoxes[k].POBox << "] count = "
	       << myBoxes[k].mailCount << endl;
    }
}

int main()
{
    MailBoxes boxes;

    cout << "after file processing" << endl;

    ifstream input("mail.dat");
    boxes.processMail(input);
    boxes.printAll(cout);
}