Grading Calc Revised

#include <iostream>
#include <string>
#include <limits>
#include <cmath>
#include <iomanip>
#include <fstream>

using namespace std;

void gradeCalc(int studentID, int count, double midterm, double finalExam, double researchPaper, double groupProject, double participation, double studentAvg, double& overallAvg, double gradeSum, char letterGrade);
void printGrade(int studentID, int count, double midterm, double finalExam, double researchPaper, double groupProject, double participation, double studentAvg, double& overallAvg, char letterGrade);

int main()
{
    int studentID;
    int count = 0;

    double midterm;
    double finalExam;
    double researchPaper;
    double groupProject;
    double participation;
    double studentAvg;
    double overallAvg;
    double gradeSum;
    char letterGrade;

    gradeCalc(studentID, count, midterm, finalExam, researchPaper, groupProject, participation, studentAvg, overallAvg, gradeSum, letterGrade);
    printGrade(studentID, count, midterm, finalExam, researchPaper, groupProject, participation, studentAvg, overallAvg, letterGrade);

    return 0;
}

void printGrade(int studentID, int count, double midterm, double finalExam, double researchPaper, double groupProject, double participation, double studentAvg, double& overallAvg, char letterGrade)
{

    ifstream infile;
    ofstream outfile;

    infile.open("grades.dat");
    outfile.open("grades.txt");
    outfile << "STUDENT GRADING REPORT: ";
    outfile << fixed << showpoint << setprecision(2);

    while (!infile.eof()) {

        infile >> studentID >> midterm >> finalExam >> researchPaper >> groupProject >> participation;

        if (studentID > 1 && studentID <= 999) {
            count++;

            outfile << endl
                    << "Student ID: " << studentID << ' ' << "Midterm: " << midterm << ' ' << "Final Exam: " << finalExam << ' ' << "Research Paper: " << researchPaper << ' ' << "Group Project: " << groupProject
                    << "Participation: " << participation << ' ' << "Student Average: " << studentAvg << ' ' << "Letter Grade: " << letterGrade;
        }
    }
    outfile << endl
            << "Total # of Students: " << count << ' ' << "Overall Class Average: " << overallAvg;

    infile.close();
    outfile.close();
};

void gradeCalc(int studentID, int count, double midterm, double finalExam, double researchPaper, double groupProject, double participation, double studentAvg, double& overallAvg, double gradeSum, char letterGrade)
{

    //midterm = .25
    //finalExam = .25
    //researchPaper = .20
    //groupProject = .20
    //participation = .10

    ifstream infile;
    ofstream outfile;

    infile.open("grades.dat");

    while (!infile.eof()) {

        infile >> studentID >> midterm >> finalExam >> researchPaper >> groupProject >> participation;
        studentAvg = ((midterm * .25) + (finalExam * .25) + (researchPaper * .20) + (groupProject * .20) + (participation * .10));

        if (studentID > 1 && studentID <= 999) {
            count++;
            gradeSum += studentAvg;

            if (studentAvg >= 90) {
                letterGrade = 'A';
            }
            else if (studentAvg >= 80 && studentAvg <= 89.99) {
                letterGrade = 'B';
            }
            else if (studentAvg >= 70 && studentAvg <= 79.99) {
                letterGrade = 'C';
            }
            else if (studentAvg < 70) {
                letterGrade = 'F';
            }

            cout << endl
                 << fixed << showpoint << setprecision(2) << "Student ID: " << studentID << ' ' << "Average:  " << studentAvg << ' ' << "Letter Grade: " << letterGrade;
        }
        if (count != 0) {
            overallAvg = (gradeSum / (count + 1));
        }
    }
    cout << endl
         << "Total # of Students: " << count << ' ' << "Overall Class Average: " << overallAvg;

    infile.close();
};