Grade Calculator (Functions, Ugh)

[beachteacher]

Program compiles but writes "invalid letter grade" to file. Am very new to programming.

// This program calculates a final grade using a formula, assigns a 
// corresponding letter grade, and outputs a "witty" comment to the user.
//******************************************************************************

#include <iostream>
#include <fstream>     // For file I/O  
#include <string>
#include <iomanip>
#include <cmath>

using namespace std;

// Declare function prototypes
void OpenFiles(ifstream&, ofstream&);
// Pre:
// Post:  File names have been prompted for and files are opened;
//        Input file name has been written on output file

void GetAndPrintStudent (ifstream&, ofstream&);
// Pre:
// Post:  Name has been read from inFile and written on outFile

void InputGrades (ifstream&, float&, float&, float&, float&, float&, float&,
                  float&, float&, float&);    
// Pre:  inFile is assigned and not empty
// Post:  Grades have been read from inFile 

float CalculateGrades (ifstream&, ofstream&, float, float, float, float);
// Pre:
// Post:  

char GetLetterGrade (ifstream&, ofstream&, char, float);
// Pre:
// Post:  

string GetWittyComment(ifstream&, ofstream&, char, string);
// Pre:
// Post: 

void PrintGrades (ofstream&);
// Pre:
// Post:  PrintGrades prints grade earned for each grade type, overall numeric
// grade, equivalent letter grade, and witty comment have been written to the 
// console and outFile

int main()
{
 // Declare and open files
 ifstream inFile;
 ofstream outFile;
 float totalHwPts = 0, totalPrgrmPts = 0, totalExamPts = 0, maxHwPts, 
       maxPrgrmPts, maxExamPts, hwPercent, prgrmPercent, examPercent, hwPart,
       prgrmPart, examPart, finalGrd; 
 char LETTERGRADE;
 string WittyComment; 
 
 OpenFiles (inFile, outFile);
 if (!inFile || !outFile)                   
 {
    cout << "Error opening files " << endl;  
    outFile << "Error opening files " << endl;      
    return 1;                               
 }  
 GetAndPrintStudent (inFile, outFile);
 
 InputGrades (inFile, totalHwPts, totalPrgrmPts, totalExamPts, maxHwPts,
              maxPrgrmPts, maxExamPts, hwPercent, prgrmPercent, examPercent); 
 
 CalculateGrades (inFile, outFile, hwPart, prgrmPart, examPart, finalGrd); 
 
 GetLetterGrade (inFile, outFile, LETTERGRADE, finalGrd);
 
 GetWittyComment(inFile, outFile, LETTERGRADE, WittyComment);
 
 PrintGrades (outFile);
  
 inFile.close();
 outFile.close();
 
 system ("pause");
 
 return 0;
}

//******************************************************************************

void OpenFiles (ifstream& inFile, ofstream& outFile)
{ 
 string inFileName;	    // User-specified input file name
 string outFileName;	// User-specified output file name
 cout << "Enter the name of the input file." << endl;
 cin >> inFileName;
 inFile.open(inFileName.c_str());
 cout << "Enter the name of the output file." << endl;
 cin >> outFileName;
 outFile.open(outFileName.c_str());
 cout << "Grade calculator for students on " << inFileName << endl;
 outFile << "Grade calculator for students on " << inFileName << endl;
 outFile << fixed;
}
 
//******************************************************************************

void GetAndPrintStudent (ifstream& inFile, ofstream& outFile)
{
 string line;
 getline(inFile, line);  // Process student name
 cout << "Student Name:  " << setw(25) << line << endl;
 outFile << "Student Name:  " << setw(25) << line << endl;
}

//******************************************************************************
 
void InputGrades (ifstream& inFile, float& totalHwPts, float& totalPrgrmPts, 
                  float& totalExamPts, float& maxHwPts, float& maxPrgrmPts, 
                  float& maxExamPts, float& hwPercent, float& prgrmPercent, 
                  float& examPercent)   
{ 
 int count, numHw, numPrgrm, numExam;
 float hwGrade, prgrmGrade, examGrade; 
       
 inFile >> numHw;
 inFile >> maxHwPts;
 count = 0;
 totalHwPts = 0;
 while (count < numHw)
 {
       inFile >> hwGrade;
       totalHwPts = totalHwPts + hwGrade;
       count ++;
 }
 inFile >> hwPercent;
 
 inFile >> numPrgrm;
 inFile >> maxPrgrmPts;
 count = 0;
 totalPrgrmPts = 0;
 while (count < numPrgrm)
 {
       inFile >> prgrmGrade;
       totalPrgrmPts = totalPrgrmPts + prgrmGrade;
       count ++;
 }
 inFile >> prgrmPercent;
 
 inFile >> numExam;
 inFile >> maxExamPts;
 count = 0;
 totalExamPts = 0;
 while (count < numExam)
 {
       inFile >> examGrade;
       totalExamPts = totalExamPts + examGrade;
       count ++;
 }
 inFile >> examPercent;
}
 
//******************************************************************************
 
float CalculateGrades (ifstream& inFile, ofstream& outFile, float hwPart,                        
                       float prgrmPart, float examPart, float finalGrd)
{
 float totalHwPts, totalPrgrmPts, totalExamPts, maxHwPts, maxPrgrmPts, maxExamPts, 
      hwPercent, prgrmPercent, examPercent;
 if (maxHwPts > 0)
 {
     hwPart = (totalHwPts/maxHwPts) * (hwPercent);
     return hwPart;
 } 
 if (maxPrgrmPts > 0)
 {
     prgrmPart = (totalPrgrmPts/maxPrgrmPts) * (prgrmPercent);
     return prgrmPart;
 } 
 if (maxExamPts > 0)
 {
     examPart = (totalExamPts/maxExamPts) * (examPercent); 
     return examPart;
 }
 else
 { 
     cout << "Error!" << endl;
     outFile << "Error!" << endl;
 }
 finalGrd = (hwPart + prgrmPart + examPart)* 100;
 return finalGrd;
}

//******************************************************************************

char GetLetterGrade (ifstream& inFile, ofstream& outFile, char LETTERGRADE, 
                     float finalGrd)
{
 if (finalGrd <= 60)
 {
 return LETTERGRADE;
 LETTERGRADE = 'F';
 }
 else if (finalGrd <=69)
 {
 return LETTERGRADE;
 LETTERGRADE = 'D';
 }
 else if (finalGrd <=79)
 {
 return LETTERGRADE;
 LETTERGRADE = 'C';
 }
 else if (finalGrd <=89)
 {
 return LETTERGRADE; 
 LETTERGRADE = 'B';
 }
 else if (finalGrd <=100)
 {
 return LETTERGRADE; 
 LETTERGRADE = 'A';
 }
}

//******************************************************************************

string GetWittyComment(ifstream& inFile, ofstream& outFile, char LETTERGRADE,
                       string WittyComment)
{
 switch (LETTERGRADE)
 { 
    case 'A':  return WittyComment;
               WittyComment = "A teacher's pet, I see!";
               break;
    case 'B':  return WittyComment;
               WittyComment = "You're doing an awesome job!";
               break;
    case 'C':  return WittyComment;
               WittyComment = "Keep your grades up.";
               break;
    case 'D':  return WittyComment;
               WittyComment = "Pick up the pace a bit more."; 
               break;
    case 'F':  return WittyComment;
               WittyComment = "Do you want to flip burgers for the rest of your life?";
               break;    
               default:  cout << LETTERGRADE << " is not a valid letter grade."
                              << endl;
                         outFile << LETTERGRADE << " is not a valid letter grade."
                              << endl;
               break;
 }
} 
//******************************************************************************

void PrintGrades(ofstream& outFile) 

{
 float hwPart, prgrmPart, examPart, finalGrd;
 char LETTERGRADE;
 string WittyComment;
 
 cout << "Homework Grade is:  " << fixed << setprecision(2) << setw(22) 
         << hwPart << "." << endl;
 outFile << "Homework Grade is:  " << fixed << setprecision(2) << setw(22) 
         << hwPart << "." << endl;
         
 cout << "Program Grade is:  " << fixed << setprecision(2) << setw(22) 
         << prgrmPart << "." << endl;
 outFile << "Program Grade is:  " << fixed << setprecision(2) << setw(22) 
         << prgrmPart << "." << endl;
         
 cout << "Exam Grade is:  " << fixed << setprecision(2) << setw(22) 
         << examPart << "." << endl;
 outFile << "Exam Grade is:  " << fixed << setprecision(2) << setw(22) 
         << examPart << "." << endl;

 cout << "Final Grade is:  " << fixed << setprecision(2) << setw(22) 
         << finalGrd << "." << endl;
 outFile << "Final Grade is:  " << fixed << setprecision(2) << setw(22) 
         << finalGrd << "." << endl;

 cout << "You earned an:  " << fixed << setprecision(2) << setw(22) 
         << LETTERGRADE << "." << endl;
 outFile << "You earned an:  " << fixed << setprecision(2) << setw(22) 
         << LETTERGRADE << "." << endl;
 
 cout << WittyComment << fixed << setprecision(2) << setw(22) << endl;
 outFile << WittyComment << fixed << setprecision(2) << setw(22) << endl;                    
}




 

[MiiNiPaa]

Return statemen will stop function immediatly. In your case problem not in "is not a valid letter grade." writing to a file, but that other cases will never executes. Put return statement at the end of a function or instead of brakes (not recommended).