c++ assignment problem : General Discussion

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <cctype>
#include <cmath>
#include <iomanip>

using namespace std;

struct TempData
{
 int day;
 int low;
 int high;
 int normal;
};

void generate_report(ifstream& fin, ostream& out);
bool read_record(ifstream& fin, TempData& t);
void write_record(ostream& out, TempData& t);

int main()
{
 ifstream mainfin;
 ofstream mainfout;
 char infilename[20];
 char outfilename[20];
 char sorfanswer;

 cout << "Welcome to the temperature report generator\n";
 cout << "Enter the name of the temperature data file: ";
 cin >> infilename;
 mainfin.open(infilename);
 if (mainfin.fail( ))
 {
  cout << "Input file opening failed.\n";
  exit(1);
 }
 do
 {
  cout << "Send report to screen or to a file? ";
  cin >> sorfanswer;
 } while (! (toupper(sorfanswer) == 'S' || toupper(sorfanswer) == 'F'));

  if (toupper(sorfanswer) == 'F')
 {
  cout << "Enter the name of the file to store the report: ";
  cin >> outfilename;
  mainfout.open(outfilename);
 
  if (mainfout.fail( ))
  {
   cout << "Output file opening failed.\n";
   exit(1);
  }
 
  generate_report(mainfin,mainfout);
  cout << "Report written to file \"" << outfilename << "\"\n";
  mainfout.close();
 }
 
 else if (toupper(sorfanswer) == 'S')
 {
  generate_report(mainfin,cout);
 }

 mainfin.close();
 cout << "\nReport generation completed.\n";
 return 0;

}


void generate_report(ifstream& fin, ostream& out)
{

 TempData t;

 while(read_record(fin,t))
 {
  write_record(out,t);
 }

}

bool read_record(ifstream& fin, TempData& t)
{
 
 
 char ch;

 fin >> t.day >> ch;
 fin >> t.low >> ch;
 fin >> t.high >> ch;
 fin >> t.normal;
 
 return (!fin.eof());

}

void write_record(ostream& out, TempData& t)
{

 out << t.day << "," << t.low << "," << t.high << "," << t.normal << endl;

}