Thread: Printing From Class/Struct

Does anyone know why my GenerateReports function is not printing anything from the class/struct? Is it even set up right?

Code:

// Example for reading records from the input files for DB.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

const int Max_Stud = 30;  //Max. no. of enrolled students

struct NameType
{
    string last;
    string first;
    char middle;
};

struct CourseType 
{
    string name;
    char grade;
    int credits;

};

struct  StudRecType 
{
    string ssno;
    NameType name;
    string tel;
    char gender;
    string level;
    int totalCredit;
    float cumGPA;
    int noCo;
    CourseType course[5];
    int semCredit;
    float semGPA;
};

typedef StudRecType StudDBType[Max_Stud];
    // Type definition for an array of records

class DBType
{
    public: 
        DBType( );
        void Insert(StudRecType );
        bool GetNext(StudRecType &);
        void Reset( );
    private:
        StudDBType Stud;
        int current;
        int nost;
};    

DBType::DBType( )
{
    current = 0;
    nost = 0;
}

void DBType:: Insert(StudRecType  srec)
{
    Stud[current] = srec;
    current ++;
    nost ++;
}

bool  DBType::GetNext (StudRecType & srec)
{
    if(current > nost)
        return false;
    else
    {
        srec = Stud[current];
        current ++;
        return true;
    }
}

void DBType::Reset ( )
{
    current = 0;
}

void Get_Inf (ifstream&, DBType&, int&);

void  UpdateGPA(StudRecType&);  // Calculate Sem. GPA and Cum GPA etc…
void  GenerateReports(ofstream&, DBType&, int&);

void GenerateReports(ofstream& printFile, DBType& displayDB, int& noStud)
{
	StudRecType student;

    int i = 0;

    for (i = 1; i < noStud; i++)
    {
		cout << "SS#: " << student.ssno << endl;
		cout << "Name(last, first, mid): " << student.name.last << " " << student.name.last << " " << student.name.middle << endl;
		cout << "Telphon Number: " << student.tel << endl;
		cout << "Gender: " << student.gender;
		cout << "Class Level: " << student.level;
		if (student.noCo > 0)
		{
			cout << "Registration of Spring 2008: Yes" << endl;
			int j = 0;

			for (j = 0; j < student.noCo; j++)
			{
				cout << "Unoffical Report Card" << endl;
				cout << "Course: " << j << endl;
				cout << student.course[j].name;
				cout << "Credits: " << endl; 
				cout << student.course[j].credits << endl;
				cout << "Grade: " << endl;
				cout << student.course[j].grade << endl;

				displayDB.GetNext(student);
			}
			
			cout << "Credits for Spring: " << student.semCredit << endl;
			cout << "Spring Semester GPA: " << student.semGPA << endl;
			cout << "Total Credits: " << student.totalCredit + student.semCredit << endl;
			cout << "New cumulative GPA: " << student.cumGPA << endl;
		}

		else
		{
			cout << "Registration of Spring 2008: No";
		}
		
		displayDB.GetNext(student);

	}

}
void UpdateGPA(StudRecType& fGPA)
{
    int count = 0;
    int i = 0;
    float gradeA = 4.0;
    float gradeB = 3.0;
    float gradeC = 2.0;
    float gradeD = 1.0;
    float gradeF = 0.0;

    float heldGPA = 0.0;
    float totalGPA = 0.0;

    count = fGPA.noCo;

    int amtClass = 0;
    
    if (fGPA.noCo != 0)
    {
        for (i = 0; i < count; i++)
        {
            if (fGPA.course[i].grade == 'A')
            {
                heldGPA =gradeA * fGPA.course[i].credits;
                amtClass= amtClass + fGPA.course[i].credits;
            }
            if (fGPA.course[i].grade == 'B')
            {            
                heldGPA =gradeB * fGPA.course[i].credits;
                amtClass= amtClass + fGPA.course[i].credits;
            }
            if (fGPA.course[i].grade == 'C')
            {
                heldGPA =gradeC * fGPA.course[i].credits;
                amtClass= amtClass + fGPA.course[i].credits;
            }
            if (fGPA.course[i].grade == 'D')
            {            
                heldGPA =gradeD * fGPA.course[i].credits;
                amtClass= amtClass + fGPA.course[i].credits;
            }
            if (fGPA.course[i].grade == 'F')
            {            
                heldGPA =gradeF * fGPA.course[i].credits;
                amtClass= amtClass + fGPA.course[i].credits;
            }
            if (fGPA.course[i].grade == 'W')

             totalGPA = (heldGPA + totalGPA);
        }
            fGPA.semGPA = (totalGPA / amtClass);
            fGPA.cumGPA = (totalGPA + fGPA.cumGPA*fGPA.totalCredit)/ (amtClass+fGPA.totalCredit);
    }

}
int main()
{
    ifstream inStud;
    ofstream outFile;
    //int choice;
    DBType StudDB;
	int noStud = 0;

    inStud.open("Stud.txt");
    
    if (!inStud)
    {
        cout <<"**Can't open input file Stud**"<< endl;
        return 1;
    }

    outFile.open("Echo.dat");
    if(!outFile)
    {
        cout <<"** Can't open output file **"<< endl;
        return 1;
    }
    Get_Inf(inStud, StudDB, noStud);


    cout << "Total no. of Students is "<<noStud<<endl;
    cout<<endl;
    GenerateReports(outFile, StudDB, noStud);
    return 0;
}

//*******************************************************************
void Get_Inf(
    /* in  */ ifstream&     inF1,
    /* out */ DBType&      DB,
	/* Number of students */ int& noStud)
{
    int j;
    int jco;
    StudRecType SR;

	noStud = 0;
    while(!inF1.eof())
    {
        inF1>>SR.ssno;
        inF1>>SR.name.last>>SR.name.first>>SR.name.middle;
        inF1>>SR.tel>>SR.gender>>SR.level;
        inF1>>SR.totalCredit>>SR.cumGPA;
        
        //Echo input data on the screen
        cout<<SR.ssno<<endl;                    
        cout<<SR.name.last<<"*"<<SR.name.first;
        cout<<"*"<<SR.name.middle<<endl;
        cout<<SR.gender<<"*"<<SR.level<<endl;
        cout<<SR.totalCredit<<"*"<<SR.cumGPA<<endl;

        inF1>>jco;
        SR.noCo = jco;
        for (j = 0;j < jco; j++)
        {                                        
            inF1>>SR.course[j].name;
            inF1>>SR.course[j].credits;
            inF1>>SR.course[j].grade;
            cout<<SR.course[j].name
                <<","<<SR.course[j].credits<<","
                <<SR.course[j].grade<<endl;

        }
        noStud++;
        UpdateGPA(SR);
        DB.Insert (SR);
        inF1.ignore(100,'\n');
        cin.get();
    }    
}

Have you checked the result of GetNext()? I'll let you figure out why.

I suspect you will find it returning false. Also, the first iteration of the loop in GenerateReports will write "rubbish", as the student record is uninitilized.

--
Mats

The function for getnext should be right as it was given to us by the professor, I haven't touched it. Also I don't understand why the first iteration would not work. I will keep working on it thanks for the help!.

Edit: I am actually starting to think that I don't need to call getnext within the second forloop for the printing of the courses although I am not sure.

You are right that you don't need to call GetNext twice in the big loop [at least, I don't think that's right].

And I don't mean to say that GetNext() as a function is broken, in and of itself. I believe it's the way that you use it that makes it "not work".

However to your two objections:
1. What is the value of "student" in the first iteration of generatereports?
2. What value does GetNext() return? True or False?
[It is ALWAYS a good idea to check the return value from a function, particularly if it gives you some data back that you rely on].

I also, looking further at your code, I realize that you are using a form where you abbreviate "number" to "no". This is something that can easily be misconstrued - much better to use n, num or number - e.g. instead of noCo, use numCo. "noSomething" is easily misunderstood as "a flag to say we don't want Something".

--
Mats

Ok, so can you PLEASE ADD A CHECK to see the return value from GetNext()?

I'm 99% sure that's what the problem stems from [assuming you're still struggling to print something sensible].

--
Mats