C++, Keep Adding Records To a File besd on User confirmation

Below code is able to send a single student information to a file at once. How can it modified to send more records one after another without exiting and re-opening the program. I'm new for this. Kindly help.

#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <iomanip>
#include <windows.h>
#include <sstream>
#include <algorithm>
#include <conio.h>
#include <stdio.h>
#include <cstdlib>
#include <iomanip>
#include <dos.h>
using namespace std;
string userName;
string passWord;
string selection;
int option;

struct patientinfo {
    string PatientFname;
    string PatientLname;
    int Age;
    int ContactNo;
    string TreatmentType;
    string AppDate;
    string AppTime;
    int eReciptId;
};

int num;
patientinfo emp[50];
void makeBooking()
{

ofstream outputFile;
outputFile.open("smt.bin", std::ofstream::in | std::ofstream::out | std::ofstream::app);

int i=num;
num+=1;

cout<< endl << endl << endl << endl << endl << endl 
<< setw(30)<<"First Name       : ";
cin>>emp[i].PatientFname;
outputFile <<emp[i].PatientFname <<",";
cout<< setw(30)<<"Last Name        : ";
cin>>emp[i].PatientLname;
outputFile <<emp[i].PatientLname <<",";
cout<< setw(30)<<"Age        : ";
cin>>emp[i].Age;
outputFile <<emp[i].Age <<",";

}


int main ()
{
    makeBooking();

    return 0;   

}