Grading Program Error

I'm writing this grading program that calculates and displays a students grades and after all the students have been entered, it displays(or at least it should) display the group totals. The problem is, everytime i run the program, the program crashes. I can't seem to figure out why it does that. I'd really appreciate it if someone could help me out a bit. Any advice would be really helpful. Thanks!

ps. i wasn't able to calculate the
classes average grade yet.

Code:

#include <cstdlib>
#include <iostream>

using namespace std;

struct studentRecord //structure definition
{
       int studentID;
       char first_name[21];
       char last_name[11];
       int quiz_1;
       int quiz_2;
       int midterm_score;
       int final_score;
       int totalpts;
       double percent;
       char grade;
};

studentRecord student; //structure variable student

//declaring constants
const int maxpts = 200;

//declare function prototypes
bool moreStudents();
void getInput(studentRecord &myStudent);
double computePercent(int totalpts, int);
int computePointsEarned(int quiz_1, int quiz_2, int midterm_score, int final_score);
void displayRecord(studentRecord);
void displayTotals(int totalStudents, double highest, double lowest,
                   double avgPoints);
int computeHighestPoints(int numbers1, int numbers2);
int computeLowestPoints(int numbers1, int numbers2);
int computeClassPoints (int numbers1, int numbers2);
double computeAveragePoints(int allPoints, int totalStudents);
char computeGrade(double input);


int main()
{
    //declare variables
    int totalStudents = 0;
    int highest = 0;
    int lowest = 0;
    int allPoints;
    double avgPoints;
    
    //adjusts number output
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(1);
    
    do
    {
         getInput(student);
         displayRecord(student);
         student.percent = computePercent(student.totalpts, maxpts);
         student.totalpts = computePointsEarned(student.quiz_1, student.quiz_2, 
                                     student.midterm_score, student.final_score);
         student.grade = computeGrade(student.percent);
         highest = computeHighestPoints(highest, student.totalpts);
         lowest = computeLowestPoints(lowest, student.totalpts);
         allPoints = computeClassPoints(allPoints, student.totalpts);
         avgPoints = computeAveragePoints(allPoints, totalStudents);
         totalStudents++; //add 1 to student counter
         
    }while(moreStudents()); //calls the moreStudents() function
    
    displayTotals(totalStudents, highest, lowest, avgPoints);
    
    system("PAUSE");
    return 0;
    
} //end main()

//functions

bool moreStudents()

{
     bool more = false;
     char anotherStudent = 'n';
     
     cout << "\n\nWould You like to enter another student? enter 'y' or 'Y' and press ENTER; \n";
     cout << "if not, enter any other character and press ENTER ";
     
     if(anotherStudent == 'y' || anotherStudent == 'Y')
            more = true;
     else
            more = false;
            
     
     return more;

} //end anotherStudent

void getInput (studentRecord &myStudent)

{
     int ID;
     
     string message = "\n\nEnter Student ID: ";
     
     do
     {
            cout << message;
            cin >> ID;
            
            message = "\n\nError! Please Re-Enter Student ID (1-99999): ";
     
     } while (ID < 1 || ID > 99999);
     
     myStudent.studentID = ID;
     
     
     //asks user to input first and last name

            cout << "Enter First Name: ";
            cin >> myStudent.first_name;
            
            
            cout << "Enter Last Name: ";
            cin >> myStudent.last_name;



    //determines quiz #1 score
    int Quiz1;
    
    string message1 = "Please enter Quiz #1 score: ";
    
    do
    {
           cout << message1;
           cin >> Quiz1;
           
           message1 = "\n\nError! Please Re-Enter Quiz #1 score: ";
    } while (Quiz1 < 0 || Quiz1 > 25);
    
    myStudent.quiz_1 = Quiz1;
    
    //determines quiz #2 score
    int Quiz2;
    
    string message2 = "Please enter Quiz #2 score: ";
    
    do
    {
           cout << message2;
           cin >> Quiz2;
           
           message = "\n\nError! Please Re-Enter Quiz #2 2core: ";
    } while (Quiz2 < 0 || Quiz2 > 25);
    
    myStudent.quiz_2 = Quiz2;
    
    //determines midterm score
    int Midterm;
    
    string message3 = "Please enter Midterm score: ";
    
    do
    {
           cout << message3;
           cin >> Midterm;
           
           message = "\n\nError! Please Re-Enter Midterm 2core: ";
    } while (Midterm < 0 || Midterm > 50);
    
    myStudent.midterm_score = Midterm;
    
    //determines final score
    int Final;
    
    string message4 = "Please enter Final score: ";
    
    do
    {
           cout << message4;
           cin >> Final;
           
           message = "\n\nError! Please Re-Enter Final score: ";
    } while (Final < 0 || Final > 100);
    
    myStudent.final_score = Final;
    
} //end getInput()

int computeHighestPoints(int numbers1, int numbers2)
{
       if (numbers1 >= numbers2)
       return numbers1;
    else
        return numbers2;
}//end computeHighestPoints

int computeLowestPoints(int numbers1, int numbers2)
{
    if (numbers1 <=numbers2)
       return numbers1;
    else
        return numbers2;
}//end computeLowestPoints

int computeClassPoints(int numbers1, int numbers2)
{
    return (numbers1 + numbers2);
}//end computeAllPoints

double computeAveragePoints(int allPoints, int totalStudents)
{
       return (allPoints/totalStudents);
}//end computeAveragePoints
     
double computePercent(int total, int max)
{
       //calculates percentage
       int output;
       output = (maxpts)/total*100;
       return output;
} //end computePercent


int computePointsEarned(int quiz_1, int quiz_2, int midterm_score, int final_score)
{
       //calculates total points earned
       int output;
       output = quiz_1 + quiz_2 + midterm_score + final_score;
       return output;
} //end computePointsEarned

char computeGrade(double input)
{
     if (input >= 90)
        return 'A';
     else if (input >= 80)
          return 'B';
     else if (input >= 70)
          return 'C';
     else if (input >= 60)
          return 'D';
     else return 'F';
}//end computeGrade


void displayRecord(studentRecord staff)
{
     //display input data
     cout << "\n\nStudent ID: " << staff.studentID;
     cout << "\nFirst Name: " << staff.first_name;
     cout << "\nLast Name: " << staff.last_name;
     cout << "\nQuiz #1 Score: " << staff.quiz_1;
     cout << "\nQuiz#2 Score: " << staff.quiz_2;
     cout << "\nMidterm Score: " << staff.midterm_score;
     cout << "\nFinal Score: " << staff.final_score;
     cout << "\nTotal Points Earned: " << staff.totalpts;
     cout << "\nOverall Percentage: " << staff.percent;
     cout << "\nLetter Grade: " << staff.grade;
} //end of displayRecord


void displayTotals(int totalStudents, double highest, double lowest,
                   double avgPoints)
{
     cout << "\n--------------------------------------------\n\n";
     cout << "Total Students = " << totalStudents;
     cout << "\nHighest Total Points Earned = " << highest;
     cout << "\nLowest Total Points Earned = " << lowest;
     cout << "\nAverage Total Points Earned = " << avgPoints;
     cout << "\nAverage Letter Grade Earned = ???";

}//end displayTotals

Well, I'll teach you the art of debugging. Start by commenting out everything inside the main(). Then uncomment the first line, compile and run it. Repeat for the next line until you find the one that crashes the program.

care to narrow down where it's crashing?

Originally Posted by alphaoide

Well, I'll teach you the art of debugging. Start by commenting out everything inside the main(). Then uncomment the first line, compile and run it. Repeat for the next line until you find the one that crashes the program.

or you could fast forward from the 50's and use a debugger?

Well, a beginner is not yet familiar with stepping into, inserting breakpoint, etc, I suppose.

Originally Posted by alphaoide

Well, a beginner is not yet familiar with stepping into, inserting breakpoint, etc, I suppose.

well then it's a good time to learn, isn't it?

seriously, that kind of blind change/recompile/test cycle takes forever once you have any decent size of program. Learning good debugging skills early on is invaluable.

Originally Posted by ChaosEngine

care to narrow down where it's crashing?

it crashes right after it displays the student's individual record. =\

Code:

    do
    {
         getInput(student);
         displayRecord(student);
         student.percent = computePercent(student.totalpts, maxpts);  // student.totalpts is not initialized

You may want to re-order your function calls

Code:

    do
    {
         getInput(student);
         displayRecord(student);
         student.totalpts = computePointsEarned(student.quiz_1, student.quiz_2, student.midterm_score, student.final_score);
         student.percent = computePercent(student.totalpts, maxpts);

Code:

int totalStudents = 0;

...

avgPoints = computeAveragePoints(allPoints, totalStudents);
totalStudents++; //add 1 to student counter

...

double computeAveragePoints(int allPoints, int totalStudents)
{
       return (allPoints/totalStudents);
}//end computeAveragePoints

You'll have problems when calling that function the first time since totalStudents is equal to 0 the first time through the loop and you are dividing by 0 which is a no-no. The increment of totalStudents should be before you call the computeAveragePoints function and not after.

There is also a problem in that you are returning a double from that function but the function itself performs integer division which will not give you what you want. You will need to cast at least one of the arguments to type double prior to the division so that floating-point division will take place.

Code:

double computeAveragePoints(int allPoints, int totalStudents)
{
    return static_cast<double>(allPoints) / totalStudents;
}

yay! i was able to get it to work, thanks for the help! =]

here's what the code looks like:

Code:

#include <cstdlib>
#include <iostream>

using namespace std;

struct studentRecord //structure definition
{
       int studentID;
       char first_name[21];
       char last_name[11];
       int quiz_1;
       int quiz_2;
       int midterm_score;
       int final_score;
       int totalpts;
       double percent;
       char grade;
};

studentRecord student; //structure variable student

//declaring constants
const int maxpts = 200;

//declare function prototypes
bool moreStudents();
void getInput(studentRecord &myStudent);
int computePointsEarned(int quiz_1, int quiz_2, int midterm_score, int final_score);
double computePercent(int totalpts, int);
void displayRecord(studentRecord);
int computeHighestPoints(int numbers1, int numbers2);
int computeLowestPoints(int numbers1, int numbers2);
double computeAveragePoints(int allPoints, int totalStudents);
double computeAveragePercent (double avgPoints, int);
char computeGrade(double input);
void displayTotals(int totalStudents, double highest, double lowest,
                   double avgPoints, char avgGrade);


int main()
{
    //declare variables
    int totalStudents = 0;
    int highest = 0;
    int lowest = 0;
    int allPoints = 0;
    double avgPoints;
    double avgPercent;
    char avgGrade;
    
    //adjusts number output
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(1);
    
    do
    {
         getInput(student);
         student.totalpts = computePointsEarned(student.quiz_1, student.quiz_2, 
                                     student.midterm_score, student.final_score);
         student.percent = computePercent(student.totalpts, maxpts);
         student.grade = computeGrade(student.percent);
         lowest = computeLowestPoints(student.totalpts, highest);
         highest = computeHighestPoints(highest, student.totalpts);
         displayRecord(student);
         totalStudents++; //add 1 to student counter
         allPoints = allPoints + student.totalpts; //accumulates total class points
         avgPoints = computeAveragePoints(allPoints, totalStudents);
         avgPercent = computeAveragePercent(avgPoints, maxpts);
         avgGrade = computeGrade(avgPercent);
        
         
    }while(moreStudents()); //calls the moreStudents() function

    
    displayTotals(totalStudents, highest, lowest, avgPoints, avgGrade);
    
    system("PAUSE");
    return 0;
    
} //end main()

//functions

bool moreStudents()

{
     bool more = false;
     char anotherStudent = 'n';
     
     cout << "\n\nWould You like to enter another student? enter 'y' or 'Y' and press ENTER; \n";
     cout << "if not, enter any other character and press ENTER ";
     cin >> anotherStudent;
     
     if(anotherStudent == 'y' || anotherStudent == 'Y')
            more = true;
     else
            more = false;
            
     
     return more;

} //end anotherStudent

void getInput (studentRecord &myStudent)

{
     int ID;
     
     string message = "\n\nEnter Student ID: ";
     
     do
     {
            cout << message;
            cin >> ID;
            
            message = "\n\nError! Please Re-Enter Student ID (1-99999): ";
     
     } while (ID < 1 || ID > 99999);
     
     myStudent.studentID = ID;
     
     
     //asks user to input first and last name

            cout << "Enter First Name: ";
            cin >> myStudent.first_name;
            
            
            cout << "Enter Last Name: ";
            cin >> myStudent.last_name;



    //determines quiz #1 score
    int Quiz1;
    
    string message1 = "Please enter Quiz #1 score: ";
    
    do
    {
           cout << message1;
           cin >> Quiz1;
           
           message1 = "\n\nError! Please Re-Enter Quiz #1 score: ";
    } while (Quiz1 < 0 || Quiz1 > 25);
    
    myStudent.quiz_1 = Quiz1;
    
    //determines quiz #2 score
    int Quiz2;
    
    string message2 = "Please enter Quiz #2 score: ";
    
    do
    {
           cout << message2;
           cin >> Quiz2;
           
           message2 = "\n\nError! Please Re-Enter Quiz #2 2core: ";
    } while (Quiz2 < 0 || Quiz2 > 25);
    
    myStudent.quiz_2 = Quiz2;
    
    //determines midterm score
    int Midterm;
    
    string message3 = "Please enter Midterm score: ";
    
    do
    {
           cout << message3;
           cin >> Midterm;
           
           message3 = "\n\nError! Please Re-Enter Midterm 2core: ";
    } while (Midterm < 0 || Midterm > 50);
    
    myStudent.midterm_score = Midterm;
    
    //determines final score
    int Final;
    
    string message4 = "Please enter Final score: ";
    
    do
    {
           cout << message4;
           cin >> Final;
           
           message4 = "\n\nError! Please Re-Enter Final score: ";
    } while (Final < 0 || Final > 100);
    
    myStudent.final_score = Final;
    
} //end getInput()


int computePointsEarned(int quiz1, int quiz2, int midtermScore, int finalScore)
{
       //calculates total points earned
       int output;
       output = quiz1 + quiz2 + midtermScore + finalScore;
       return output;
} //end computePointsEarned

double computePercent(int total, int max)
{
       //calculates percentage
       int output;
       output = (total)*100/max;
       return output;
} //end computePercent

char computeGrade(double input)
{
     if (input >= 90)
        return 'A';
     else if (input >= 80)
          return 'B';
     else if (input >= 70)
          return 'C';
     else if (input >= 60)
          return 'D';
     else return 'F';
}//end computeGrade

int computeLowestPoints(int numbers1, int numbers2)
{
    if (numbers1 <=numbers2)
       return numbers1;
    else
        return numbers2;
}//end computeLowestPoints

int computeHighestPoints(int numbers1, int numbers2)
{
       if (numbers1 >= numbers2)
       return numbers1;
    else
        return numbers2;
}//end computeHighestPoints


double computeAveragePoints(int all, int total)
{
       int output;
       output = all/total;
       return output;
}//end computeAveragePoints

double computeAveragePercent(double avg, int max)
{
       //calculates percentage
       double output;
       output = (avg)*100/max;
       return output;
} //end computePercent     


void displayRecord(studentRecord staff)
{
     //display input data
     cout << "\n\nStudent ID: " << staff.studentID;
     cout << "\nFirst Name: " << staff.first_name;
     cout << "\nLast Name: " << staff.last_name;
     cout << "\nQuiz #1 Score: " << staff.quiz_1;
     cout << "\nQuiz#2 Score: " << staff.quiz_2;
     cout << "\nMidterm Score: " << staff.midterm_score;
     cout << "\nFinal Score: " << staff.final_score;
     cout << "\nTotal Points Earned: " << staff.totalpts;
     cout << "\nOverall Percentage: " << staff.percent;
     cout << "\nLetter Grade: " << staff.grade;
} //end of displayRecord


void displayTotals(int totalStudents, double highest, double lowest,
                   double avgPoints, char avgGrade)
{
     cout << "\n-------------------------------------------------\n\n";
     cout << "Total Students = " << totalStudents;
     cout << "\nHighest Total Points Earned = " << highest;
     cout << "\nLowest Total Points Earned = " << lowest;
     cout << "\nAverage Total Points Earned = " << avgPoints;
     cout << "\nAverage Letter Grade Earned = " << avgGrade;
     cout << "\n-------------------------------------------------\n\n";
     

}//end displayTotals