HELP--Calculations not working out

[ladibug410]

Hi! Im doing a gradebook program for class, with that has a header file and a cpp file. Once i run the program the calculations for final semester grade come up as a really long negative number. fsd has been declared already and initialized

double gradebook::getFinalSemesterGrade()//calculates final semester grade
{

fsd = (lab_avg * .50) + (quiz_avg * .10) + (midterm_exam_grade * .20) + (final_exam_grade * .20) +
(ec_grade * .02);
return fsd;
}

[NyqLy60M]

I don't believe your problem is in the code that's shown...
Are all of the variables shown here doubles?

[ladibug410]

yes, should i post all of the files, the .cpp's and the header file?

[NyqLy60M]

That would be for the best.

Please add code tags where applicable.

[ladibug410]

Thank You!

Lab1 part b.cpp

#include <iostream>
#include "gradebook.h"
#include <iomanip>


using namespace std;

int main()
{
gradebook gb, gb2;// creates two gradebook objects
double lab_grade;
double quiz_grade;
double lab_avg;
double quiz_avg;
double midterm_exam_grade;
double final_exam_grade;
double fsd;
double ec_grade;


cout << "Enter the Six Lab Grades: ";//asks user for six lab grades
cin >> lab_grade;
gb.addLabGrade(lab_grade);
gb2.addLabGrade(lab_grade);
cin >> lab_grade;
gb.addLabGrade(lab_grade);
gb2.addLabGrade(lab_grade);
cin >> lab_grade;
gb.addLabGrade(lab_grade);
gb2.addLabGrade(lab_grade);
cin >> lab_grade;
gb.addLabGrade(lab_grade);
cin >> lab_grade;
gb.addLabGrade(lab_grade);
cin >> lab_grade;
gb.addLabGrade(lab_grade);

lab_avg = gb.getAvgLabGrade();

lab_avg = gb2.getAvgLabGrade();


cout << "Enter the Seven Quiz Grades: "; // asks user for 7 quiz grades
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);
gb2.addQuizGrade(quiz_grade);
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);
gb2.addQuizGrade(quiz_grade);
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);
gb2.addQuizGrade(quiz_grade);
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);
gb2.addQuizGrade(quiz_grade);
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);
cin >> quiz_grade;
gb.addQuizGrade(quiz_grade);

quiz_avg = gb.getAvgQuizGrade();

quiz_avg = gb2.getAvgQuizGrade();


cout << "Enter Your Midterm Exam Grade: "; //asks user to put in midterm exam grade
cin >> midterm_exam_grade;
gb.setMidtermExamGrade(midterm_exam_grade);
gb2.setMidtermExamGrade(midterm_exam_grade);





cout << "Enter Your Final Exam Grade: ";// asks user to put in final exam grade
cin >> final_exam_grade;
gb.setFinalExamGrade(final_exam_grade);
gb2.setFinalExamGrade(final_exam_grade);

cout << "Enter Your Extra Credit Grade: ";//asks user for extra credit grade
cin >> ec_grade;
gb.setExtraCreditGrade(ec_grade);
gb2.setExtraCreditGrade(ec_grade);



//Output for Gradebook 1
cout << fixed << setprecision(2);// sets to two decimal places
cout << endl << endl<<"STUDENT FINAL SEMESTER GRADE CALCULATION"<<endl;
cout << "Average Lab Grade: " << gb.getAvgLabGrade() << endl;
cout << "Average Quiz Grade: " << gb.getAvgQuizGrade() << endl;
cout << "Midterm Exam Grade: " << gb.getMidtermExamGrade() << endl;
cout << "Final Exam Grade: " << gb.getFinalExamGrade() << endl;
cout << "Extra Credit Grade: " << gb.getExtraCreditGrade() << endl;
cout << "Final Semester Grade (FSG): " << gb.getFinalSemesterGrade() << endl;
cout << "Final Letter Grade: " << gb.getFinalLetterGrade() << endl;

//Output for Gradebook 2
cout << fixed << setprecision(2);//sets to two decimal places
cout << endl << endl<<"STUDENT FINAL SEMESTER GRADE CALCULATION FOR SECOND OBJECT"<<endl;
cout << "Average Lab Grade: " << gb2.getAvgLabGrade() << endl;
cout << "Average Quiz Grade: " << gb2.getAvgQuizGrade() << endl;
cout << "Midterm Exam Grade: " << gb2.getMidtermExamGrade() << endl;
cout << "Final Exam Grade: " << gb2.getFinalExamGrade() << endl;
cout << "Extra Credit Grade: " << gb2.getExtraCreditGrade() << endl;
cout << "Final Semester Grade (FSG): " << gb2.getFinalSemesterGrade() << endl;
cout << "Final Letter Grade: " << gb2.getFinalLetterGrade() << endl;

system("pause");
return 0;
}

[ladibug410]

gradebook.h

#include <string>
using namespace std;

class gradebook
{
public:
gradebook(); //member functions
void addLabGrade(double grade);
void addQuizGrade(double grade);
void setMidtermExamGrade(double grade);
void setFinalExamGrade(double grade);
void setExtraCreditGrade(double grade);
double getMidtermExamGrade();
double getFinalExamGrade();
double getFinalSemesterGrade();
char getFinalLetterGrade();
double getAvgLabGrade();
double getAvgQuizGrade();
double getExtraCreditGrade();

private://data members
double lab_grade_total;
double quiz_grade_total;
int lab_grade_cnt;
int quiz_grade_cnt;
double lab_avg;
double quiz_avg;
double midterm_exam_grade;
double final_exam_grade;
double fsd;
double ec_grade;
char letter_grade;

};




gradebook.cpp

#include <iostream>
#include "gradebook.h"

gradebook::gradebook()
{
lab_grade_total = 0.0;
lab_grade_cnt = 0;
quiz_grade_total = 0.0;
quiz_grade_cnt = 0;
fsd = 0.0;
letter_grade = ' ';
}

void gradebook::addLabGrade(double grade)
{
lab_grade_total += grade;
lab_grade_cnt++;
}
void gradebook::addQuizGrade(double grade)
{
quiz_grade_total += grade;
quiz_grade_cnt++;
}
void gradebook::setMidtermExamGrade(double grade)
{
midterm_exam_grade = grade;
}
void gradebook::setFinalExamGrade(double grade)
{
final_exam_grade = grade;
}
void gradebook::setExtraCreditGrade(double grade)
{
ec_grade = grade;
}
double gradebook::getMidtermExamGrade()
{
return midterm_exam_grade;
}
double gradebook::getFinalExamGrade()
{
return final_exam_grade;
}
double gradebook::getFinalSemesterGrade()//calculates final semester grade
{

fsd = (lab_avg * .50) + (quiz_avg * .10) + (midterm_exam_grade * .20) + (final_exam_grade * .20) +
(ec_grade * .02);
return fsd;
}
char gradebook::getFinalLetterGrade()//pieces together final letter grade
{
if( fsd > 89) letter_grade = 'A';
else if( fsd > 79) letter_grade = 'B';
else if( fsd > 69) letter_grade = 'C';
else if( fsd > 65) letter_grade = 'D';
else letter_grade = 'F';
return letter_grade;
}
double gradebook::getAvgLabGrade()//calculate average here
{
return lab_grade_total / lab_grade_cnt;
}
double gradebook::getAvgQuizGrade()
{
return quiz_grade_total / quiz_grade_cnt;
}
double gradebook::getExtraCreditGrade()
{
return ec_grade;
}

[NyqLy60M]

The gradebook() constructor should use a member initialization list.
http://www.cplusplus.com/forum/articles/17820/

As a precaution, you should add this to gradebook.h:

#ifndef GRADEBOOK_H
#define GRADEBOOK_H

// includes and etc.

class gradebook{ ... };

#endif 

_{Some information on include guards: http://stackoverflow.com/questions/1653958/why-are-ifndef-and-define-used-in-c-header-files}

When the method "getFinalSemesterGrade()" is called,
lab_avg = -9.2559631349317831e+061,
and quiz_avg = lab_avg.

_{Let's see if you can figure out why.}

[ladibug410]

I cant figure it out, whatever im doing wrong. I kept reading those articles and it still makes no sense to me. I am assuming my calculations with the lab avg and quiz avg is wrong, but those calculations were given by my teacher, so im not sure whats wrong.

[NyqLy60M]

You're using the wrong lab_avg and quiz_avg.

In gradebook.h

double getFinalSemesterGrade(double, double);

In gradebook.cpp

double gradebook::getFinalSemesterGrade(double lab_avg, double quiz_avg)
{
    fsd = (lab_avg * .50) + (quiz_avg * .10) + (midterm_exam_grade * .20)
    + (final_exam_grade * .20) + (ec_grade * .02);

    return fsd;
}

Make sure EVERY variable gets initialized, in your main() source and elsewhere, and remove lab_avg and quiz_avg inside gradebook.h.