Getting average age of students and youngest student's name - c++

Question

I'm having some trouble with getting the average age of all students including getting the youngest student's name outputted. The output is supposed to come from a function call I wrote called ageCalc(...).
main.cpp
#include <iostream>
#include <fstream>
#include <iomanip>
#include "Student1.h"
#include "Student2.h"
#include "ageCalc.h"
using namespace std;
const int SIZE = 100;
int main()
{
ifstream inFile;
inFile.open("C:\\COMSC200\\a2data.input", ios::in|ios::binary);
// Open the input file – if it fails to open, display an error message and terminate
if(!inFile.is_open())
{
cout << "Unable to open file!";
return 1;
}
else
{
cout << "File successfully open!\n\n";
}
// Use a pointer array to manage all the created student variables.
Student1 **ptrArr = new Student1 *[SIZE];
Student1 s;
int total = 0;
// read the first input record
inFile.read(reinterpret_cast<char *> (&s), sizeof(s));
while(!inFile.eof())
{
// dynamically allocate space for new student variable
ptrArr[total] = new Student1;
// populate the student variable from the input
*ptrArr[total] = s;
total++;
// read the next input record
inFile.read(reinterpret_cast<char *> (&s), sizeof(s));
}
Student2 *st = new Student2[SIZE];
for(int i = 0; ptrArr[i]; i++)
{
for(char fn: ptrArr[i]->first_name)
st[i].fn += fn;
st[i].mi = ptrArr[i]->middle_int[0];
for(char ln: ptrArr[i]->last_name)
st[i].ln += ln;
st[i].cc = ptrArr[i]->campus_code;
for(char sID: ptrArr[i]->student_ID)
st[i].sID += sID;
st[i].age = atoi(ptrArr[i]->age);
}
cout << "First Name" << setw(9)
<< "MI" << setw(15)
<< "Last Name" << setw(17)
<< "Campus Code" << setw(16)
<< "Student ID" << setw(15)
<< "Age" << endl;
cout << "===================================================================================" << endl;
for(int j = 0; st[j].age != 0; j++)
{
cout << st[j].fn << setw(8);
cout << st[j].mi << " ";
cout << st[j].ln << setw(2);
cout << st[j].cc << " ";
cout << st[j].sID << setw(16);
cout << st[j].age << " " << endl;
}
Student2 *y;
int avg = ageCalc(&st, y);
cout << "Average student age is: " << avg << " years." << endl;
cout << "Youngest student is: " << arr[i]->fn << " " << arr[i]->mi << " " << arr[i]->ln << endl;
for(int x = 0; ptrArr[x]; x++)
{
delete ptrArr[x];
}
delete [] st;
inFile.close();
return 0;
}
ageCalc.cpp
#include "Student2.h"
using namespace std;
int ageCalc(Student2 *arr[], Student2 *&y)
{
int i = 0, sum = 0, index = 0, avg;
while(arr[i] != nullptr)
{
sum = arr[i]->age + sum;
i++;
if(arr[i]->age < arr[index]->age)
{
index = i;
}
}
y = arr[index];
avg = sum / i;
return avg;
}
Student1.h
#ifndef STUDENT1_H_
#define STUDENT1_H_
#include <iostream>
using namespace std;
struct Student1
{
char first_name[10];
char middle_int[10];
char last_name[20];
char campus_code;
char student_ID[8];
char age[3];
};
#endif
Student2.h
#ifndef STUDENT2_H_
#define STUDENT2_H_
#include <iostream>
#include <string>
using namespace std;
struct Student2
{
string fn;
char mi;
string ln;
char cc;
string sID;
short int age;
};
#endif
ageCalc.h
#ifndef AGECALC_H_
#define AGECALC_H_
#include "Student2.h"
int ageCalc(Student2 *[], Student2 *&);
#endif