Drving me loopy!!!

Hi I am developing a program that prints a table of student made up deatials.
The program below works ok, but when I go to enter a new detail, it lets me do it, but then I go to end the program to display the results and all I get is the last entry I did. I want the program to print all the details the user inputs, not just the most recent one.

I think the problem is my while loop in main, can anyone see where I am going worng?

Code:

#include <iostream>

using std::cout;
using std::endl;
using std::cin;

#include <string>

using std::string;
using std::getline;

// create directory class
class Directory
{
public:
    // constructor - sets course name
    Directory ( string name )
    {
       setListName ( name );
    }
    
    // display name of list
    void setListName ( string name )
    {
       listName = name;
    }
    
    string getListName()
    {
       return listName;
    }
    
    void displayMessage()
    {
       cout << "\tSchool list for: " << getListName();
    }
    
    // student name
    string setStudentName ( string stuName )
    {
       cin.ignore();	// prevents this function being skipped
       cout << "\n\nEnter student name: ";
       getline ( cin, stuName );
       
       studentName = stuName;
       return stuName;
    }
    
    string getStudentName()
    {
       return studentName;
    }
    
    // student date of birth
    int setDob ( int bd )
    {
       cout << "\nEnter year of birth: ";
       cin >> bd;
       
       dob = bd;
       return bd;
    }
    
    int getDob()
    {
       return dob;
    }
    
    // student gender
    char setGender ( char gen )
    {
	  		
       cout << "\nEnter gender, m / f: ";
       cin >> gen;
       
       gender = gen;
       return gen;
    }
    
    char getGender()
    {
       return gender;
    }
    
private:
    string listName;	// college name
    string studentName;	// student name
    int dob; // student year of birth
    char gender; // student gender
};

// main function - driver //////////////////////////////////////////////////////
//
int main ( void )
{
   Directory dir ("MILTON COLLEGE");
   dir.displayMessage();
   
   int answer;
   
   cout << "\n\nWill you use the list: -1 to quit: ";
   cin >> answer;
   
   // quit program if no data needed
   if ( answer == -1 )
   {
      return 0;
   }
   
   // loop to input data
   while ( answer != -1 )
   {
      dir.setStudentName("");
      dir.setDob(0);
      dir.setGender('a');
      
      cout << "\nWill you add another name: -1 to show result: ";
      cin >> answer;
   }
   
   // display headings
   cout << "\nSTUDENT NAME" << "\t\t" << "D O B" << "\t\t" << "GENDER" << "\n\n";
   
   // display result of class 
   cout << dir.getStudentName() << "\t\t" << dir.getDob() << "\t\t"
   	  << dir.getGender() << endl;
   
   cin.get();  // freeze console window
   cin.ignore();

   return 0;   // indicate program ended sucsessfuly
}

You only have one dir. You need an instance of dir for each student.