I am calculating average GPA from an input file and then outputting the average to an outfile, but I'm getting weird output numbers.

I am calculating average GPA from an input file and then outputting the average to an outfile, but I'm getting weird output numbers.

here is my sample input
gender            gpa

f            3.50
m            2.60
m            2.90
f            2.40
f            3.00
m            3.20
f            4.00
m            2.45

and here is my program in C++
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>

using namespace std;

main()
{
      int numM=0;
      int numF=0;
      double averageF= 0.00;
      double averageM = 0.00;
      double gpa = 0.00;
      double totalf = 0;
      double totalm = 0;
      char gender;


      ifstream infile;
      ofstream outfile;

      infile.open ("c:\\english.txt");

      outfile.open ("c:\\english1.txt");

      outfile << fixed << showpoint;
      outfile << setprecision(2);

      infile >> gender >> gpa;

      while (infile)
      {
            switch (gender)
            {
            case 'F':
            case'f': totalf = totalf + gpa;
                  numF++;
                  break;
                  
            case 'M':
            case 'm': totalm = totalm + gpa;
                  numM++;
                  break;
            }
            infile >> gender >> gpa;
      }
      averageF = totalf / numF;
      averageM = totalm / numM;

      outfile << averageF; outfile << endl;
      outfile << averageM;
}

now here is my output

-1.#J
-1.#J

I need know what the hell that is, because its not what I should be getting. Can someone please tell me what I am doing wrong.