multiple definition, undefined reference to

Hi! I'm having trouble with a project of mine, I keep getting theese undefined reference to and multiple definitions of-errors... Could someone please take a look at it and help me with it?

my code:
main.cpp

Code:

---

#include <iostream>
#include "student.h"
#include "calc.h"
#include "calc.cpp"
using std::cin;
using std::cout;
using std::endl;

bool menu();

int main(int argc, char *argv[])
{
klass klass1; // Initiera ett objekt, "Klass", av klassen Klass
int SEL;
cout << "Menu selection:\n1.Add student data\n2.Randomize student data\n3.Exit" << endl;
cin >> SEL;
switch(SEL)
{
case 1:
klass1.addstudent();
break;
case 2:
break;
case 3:
return 0;
default:
cout << "ERROR" << endl;
}

klass1.collect();
klass1.calcaverage();
cout << "de " << klass1.numBo() << " killarnas medel \x84r " << klass1.AvGradeBoys() << "\n\n";
cout << "de " << klass1.numGi() << " tjejernas medel \x84r " << klass1.AvGradeGirls() << "\n\n";
cout << "de " << (klass1.numGi()+klass1.numBo()) << " studenternas medel \x84r " << klass1.averagegrade() << endl;

cin.ignore(255,'\n');
cin.get();
return 0;
}

---

calc.cpp

Code:

---

#include "calc.h"

klass::klass() : numG(0), numB(0), AvGradeG(0), AvGradeB(0), totGrade(0)
{
}

klass::~klass()
{
}

---

calc.h

Code:

---

#ifndef CALC_H
#define CALC_H

#include "student.h"
#define students 20


class klass{
public:
klass();
~klass();
float AvGradeGirls(){return AvGradeG;};// medelbetyg för tjejer
float averagegrade(){return totGrade;}; // medelbetyg
float AvGradeBoys(){return AvGradeB;}; // medelbetyg för killar
void addstudent();
int numBo(){return numB;}; // Antal B
int numGi(){return numG;}; // Antal G
int totalStudents(){return numG+numB;}; // Totala antalet studneter
void collect();
void calcaverage();
protected:
private:
student stud[students];
int Ggrade;
int Bgrade; // Tjejsor och killsars sammanlagda betyg (ej medelvärde)
int numG;
int numB;
double AvGradeB; // Gossars betyg
double AvGradeG; // Flickors betyg
double totGrade; // Totala betyget
};

void klass::collect()
{

for(int i=(numG+numB);i>0;i--)
{
if(stud.getGender()) // om getGender() är sann = tösabete...
{
Ggrade=Ggrade+stud.getGrade();
numG++;
}
else // ...annars en hane
{
Bgrade=Bgrade+stud.getGrade();
numB++;
}
}
}
void klass::calcaverage()
{
if(numG>0) // Inte dela med noll
AvGradeG=Ggrade/numG;
if(numB>0) // inte dela med noll
AvGradeB=Bgrade/numB;
if((numB+numG)>0) // inte dela med noll
totGrade=(Bgrade+Ggrade)/(numB+numG);
}
#endif // CALC_H

---

Student.h

Code:

---

/* Skapar elever, tilldelar dem kön samt betyg */


#ifndef STUDENT_H
#define STUDENT_H

#include <iostream>

class student
{
public:
student();
virtual ~student();
void setGender(); // FALSE=boy, TRUE=girl
void giveGrade();
float getGrade(){return grade;};
bool getGender(){return gender;};
protected:
private:
bool gender;
double grade;
};



// Funktioner

void student::setGender()
{
bool sex;
std::cout << "Specify sex of student; 1 (girl) or 0 (boy): ";
std::cin >> sex;
gender=(sex=0?0:1);
}

void student::giveGrade()
{
std::cout << "Specify student grade: (1-5) ";
std::cin >> grade;
}

#endif // STUDENT_H

---

In your main( ) funcition:

Code:

---

#include "calc.cpp"

---

You do not need to include the .cpp implementation of your class. Your compiler will automatically look for and include the .cpp file with the same name as the .h header file (if one exists)


Also, in calc.h:

Code:

---

#include "student.h"

---

I do not see a reason you need to include student.h

noted and fixed. However, some errors still remain.
have a look :
www.falconvent.com/error.png

Quote:

---

Originally Posted by The Brain

Also, in calc.h:

Code:

---

#include "student.h"

---

I do not see a reason you need to include student.h

---

Look here: (calc.h)

Code:

---

private:
student stud[students];

---

I am trying to use nested classes to learn, but up untill now, its been all trouble.

I notice a lack using namespace in your .h header files

[edit]Ok, you used std:: [/edit]

Quote:

---

Originally Posted by The Brain

I notice a lack using namespace in your .h header files

---

Why do i need them? Look at the picture i took. Those three problems are the oonly ones left. How can I solve those?

Your student.h file includes iostream.. and is chocked full of cin and cout operations.. which are derived from the standard namespace.

Also, I don't think 'student' is working for you as a datatype in your calc class... because I don't think the student class is compiling.. mainly due to this error:

Code:

---

float getGrade(){return grade;};
bool getGender(){return gender;};

---

[edit]I just checked it out and my compiler will also accept a ; after an inlined function, so no error there[/edit]

Yeah, but I've declared all teh cout and cin operations as std::...
What can I do about the error? I don't even see that that is an error!

I kind of re-arranged things here.. I put all the classes in a header file by themselves, replaced inline functions.. I commented out or removed any functions that caused a linker error. Everything here compiles. Take a look and compare to what ye' got and slowly work up to what you want from code that compiles.


student.h

Code:

---

/* Skapar elever, tilldelar dem kön samt betyg */


#ifndef STUDENT_H
#define STUDENT_H

#include <iostream>

using std::cin;
using std::cout;

class student
{
public:

    //student();
    //~student();
    void setGender(); // FALSE=boy, TRUE=girl
    void giveGrade();
    float getGrade();//{return grade;}
    bool getGender();//{return gender;}

private:

    bool gender;
    double grade;
};

#endif // STUDENT_H

---

student.cpp

Code:

---

#include "student.h"
using namespace std;
// Funktioner

void student::setGender()
{
    bool sex;
    std::cout << "Specify sex of student; 1 (girl) or 0 (boy): ";
    std::cin >> sex;
    gender=(sex=0?0:1);
}

void student::giveGrade()
{
    std::cout << "Specify student grade: (1-5) ";
    std::cin >> grade;
}

float student::getGrade()//{return grade;}
{
        return grade;
}

bool student::getGender()//{return gender;}
{
        return gender;
}

---

calc.h

Code:

---

#ifndef CALC_H
#define CALC_H
 
#include"student.h"
#define students 20




class klass : public student
{
public:

    klass();
    ~klass();
    float AvGradeGirls();//{return AvGradeG;} medelbetyg för tjejer
    float averagegrade();//{return totGrade;} medelbetyg
    float AvGradeBoys();//{return AvGradeB;}  medelbetyg för killar
    //void addstudent();  //This function was never defined
    int numBo();//{return numB;}  Antal B
    int numGi();//{return numG;}  Antal G
    int totalStudents(){return numG+numB;} // Totala antalet studneter
    void collect();
    void calcaverage();


private:

    student stud[students];
    int Ggrade;
    int Bgrade; // Tjejsor och killsars sammanlagda betyg (ej  medelvärde)
    int numG;
    int numB;
    double AvGradeB; // Gossars betyg
    double AvGradeG; // Flickors betyg
    double totGrade; // Totala betyget
};

#endif // CALC_H

---

calc.cpp

Code:

---

#include "calc.h"
#include "student.h"
using namespace std;


klass::klass() : numG(0), numB(0), AvGradeG(0), AvGradeB(0), totGrade(0)
{
}

klass::~klass()
{
}

void klass::collect()
{       

        for(int i=(numG+numB);i>0;i--)
        {
                if(getGender()) // om getGender() är sann = tösabete...
                {
                        Ggrade=Ggrade+getGrade();
                        numG++;
                }

                else // ...annars en hane
                {
                        Bgrade=Bgrade+getGrade();
                        numB++; 
                }
        }
}


void klass::calcaverage()
{
        if(numG>0) // Inte dela med noll
                AvGradeG=Ggrade/numG;

        if(numB>0) // inte dela med noll
                AvGradeB=Bgrade/numB;

        if((numB+numG)>0) // inte dela med noll
                totGrade=(Bgrade+Ggrade)/(numB+numG);
}

float klass::AvGradeGirls()//{return AvGradeG;}// medelbetyg för tjejer
{
        return AvGradeG;
}

float klass::averagegrade()//{return totGrade;} // medelbetyg
{
        return totGrade;
}


float klass::AvGradeBoys()//{return AvGradeB;} // medelbetyg för killar
{
        return AvGradeB;
}

int klass::numBo()//{return numB;}  Antal B
{
        return numB;
}

int klass::numGi()//{return numG;}  Antal G
{
        return numG;
}

---

main.cpp

Code:

---

#include <iostream>
#include "calc.h"
#include "student.h"

using std::cin;
using std::cout;
using std::endl;

bool menu();

int main(int argc, char *argv[])
{
    int SEL;

    klass klass1; // Initiera ett objekt, "Klass", av klassen Klass

    cout << "Menu selection:\n1.Add student data\n2.Randomize    student data\n3.Exit" << endl;

    cin >> SEL;

    switch(SEL)
    {
          case 1:  //klass1.addstudent();  //ERROR HERE
          break;

          case 2:
          break;

          case 3:
          return 0;

          default:  cout << "ERROR" << endl;
    }

    klass1.collect();
    klass1.calcaverage();
    cout << "de " << klass1.numBo() << " killarnas medel \x84r " <<  klass1.AvGradeBoys() << "\n\n";
    cout << "de " << klass1.numGi() << " tjejernas medel \x84r " << klass1.AvGradeGirls() << "\n\n";
    cout << "de " << (klass1.numGi()+klass1.numBo()) << " studenternas medel \x84r " << klass1.averagegrade() << endl;

    cin.ignore(255,'\n');
    cin.get();
    return 0;
}

---

--------------------Configuration: main - Win32 Debug--------------------
Compiling...
calc.cpp
student.cpp
main.cpp
Linking...

main.exe - 0 error(s), 0 warning(s)

You don't have to change things around like The Brain showed you. All you need to do is add the array subscript when you use the stud array. So instead of

Code:

---

stud.getGrade()

---

it should be

Code:

---

stud[i].getGrade()

---

Or similar.

Okey, I'm back at it now.
This is how everything looks at this moment:

main.cpp

Code:

---

#include <iostream>
#include "student.h"
#include "calc.h"
//#include "calc.cpp"
using std::cin;
using std::cout;
using std::endl;

bool menu();

int main(int argc, char *argv[])
{ 
    int SEL;
    klass klass1;        // Initiera ett objekt, "Klass", av klassen Klass   
    cout << "Menu selection:\n1.Add student data\n2.Randomize student data\n3.Exit" << endl;
    cin >> SEL;
    switch(SEL)
    {
        case 1:
            klass1.addstudent();
        break;
        case 2:
            cout << "not implemented yet!";
        break;
        case 3:
            return 0;
        default:
            cout << "ERROR" << endl;
        }
        klass1.collect();
        klass1.calcaverage();
        cout << "Boys average score:\n----------------------\nNumber of boys:" << klass1.numBo() << "\nAverage score:" << klass1.AvGradeBoys() << endl << endl;
        cout << "Girls average score:\n----------------------\nNumber of girls:" << klass1.numGi() << "\nAverage score:" << klass1.AvGradeGirls() << endl << endl;
        cout << "Total average score:\n----------------------\nNumber of students:" << (klass1.numGi()+klass1.numBo()) << "\nAverage score:" << klass1.averagegrade() << endl;
       
    cin.ignore(255,'\n');
    cin.get();
    return 0;
}

---

calc.cpp

Code:

---

#include "calc.h"
#include "student.h"
using namespace std;


klass::klass() : numG(0), numB(0), AvGradeG(0), AvGradeB(0), totGrade(0)
{
}

klass::~klass()
{
}

void klass::collect()
{       

        for(int i=(numG+numB);i>0;i--)
        {
                if(getGender())            // om getGender() är sann = tösabete...
                {
                        Ggrade=Ggrade+getGrade();
                        numG++;
                }

                else                        // ...annars en hane
                {
                        Bgrade=Bgrade+getGrade();
                        numB++; 
                }
        }
}


void klass::calcaverage()
{
        if(numG>0)                      // Inte dela med noll
                AvGradeG=Ggrade/numG;

        if(numB>0)                      // inte dela med noll
                AvGradeB=Bgrade/numB;

        if((numB+numG)>0)              // inte dela med noll
                totGrade=(Bgrade+Ggrade)/(numB+numG);
}

float klass::AvGradeGirls()        // medelbetyg för tjejer
{
        return AvGradeG;
}

float klass::averagegrade()        // medelbetyg
{
        return totGrade;
}

int klass::totalStudents()
{
    return numG+numB;
}


float klass::AvGradeBoys()          // medelbetyg för killar
{
        return AvGradeB;
}

int klass::numBo()                  //  Antal B
{
        return numB;
}

int klass::numGi()                  // Antal G
{
        return numG;
}

void klass::addstudent()
{
        numofstud++;
        stud[numofstud].setGender();
        stud[numofstud].giveGrade();
}

---

student.cpp

Code:

---

#include "student.h"
using namespace std;
// Funktioner

void student::setGender()        // FALSE=boy, TRUE=girl
{ 
    bool done = false;
    while (!done)
    {
        int num;
        std::cout << "Specify sex of student; 1 (girl) or 0 (boy): ";
        std::cin >> num;
        switch( num )
        {
            case 0:
                gender = false;
                done = true;
                break;
            case 1:
                  gender = true;
                  done = true;
                  break;
              default:
                  std::cout << "You must enter 0 or 1: " << endl;
        }
    }
}

void student::giveGrade()
{
    std::cout << "Specify student grade: (1-5) ";
    std::cin >> grade;
}

float student::getGrade()
{
        return grade;
}

bool student::getGender()
{
        return gender;
}

---

calc.h

Code:

---

#ifndef CALC_H
#define CALC_H
 
#include"student.h"
#define students 20




class klass : public student
{
public:

    klass();
    ~klass();
    float AvGradeGirls();      //{return AvGradeG;} medelbetyg för tjejer
    float averagegrade();      //{return totGrade;} medelbetyg
    float AvGradeBoys();      //{return AvGradeB;}  medelbetyg för killar
    void addstudent();
    int numBo();              // Antal B
    int numGi();              // Antal G
    int totalStudents();      // Totala antalet studneter
    void collect();
    void calcaverage();


private:

    student stud[students];
    int Ggrade;
    int Bgrade;                // Tjejsor och killsars sammanlagda betyg (ej  medelvärde)
    int numofstud;
    int numG;
    int numB;
    double AvGradeB;          // Gossars betyg
    double AvGradeG;          // Flickors betyg
    double totGrade;          // Totala betyget
};

#endif // CALC_H

---

student.h

Code:

---

/* Skapar elever, tilldelar dem kön samt betyg */


#ifndef STUDENT_H
#define STUDENT_H

#include <iostream>

using std::cin;
using std::cout;

class student
{
public:

    //student();
    //~student();
    void setGender();      // FALSE=boy, TRUE=girl
    void giveGrade();
    float getGrade();      //{return grade;}
    bool getGender();      //{return gender;}

private:

    bool gender;
    double grade;
};

#endif // STUDENT_H

---

My program compiles at this point, but when I try to run it, I get into the menu, start adding data for a new student, and when I've entered the gender, the program crashes! Help, anyone?

what do you see happening when you step through you code with the debugger..?

This is the state now; I can start it, add students and everything is fine, but when I have added a few students, and go check on the statistics, the stats are all blank!
Example run:

Quote:

---

Menu selection:
1.Add student data
2.Randomize student data
3.show statistics
4.Exit
1
Specify sex of student; 1 (girl) or 0 (boy): 0
Specify student grade: (1-5) 5
Menu selection:
1.Add student data
2.Randomize student data
3.show statistics
4.Exit
1
Specify sex of student; 1 (girl) or 0 (boy): 0
Specify student grade: (1-5) 1
Menu selection:
1.Add student data
2.Randomize student data
3.show statistics
4.Exit
3
Boys average score:
----------------------
Number of boys:0
Average score:0

Girls average score:
----------------------
Number of girls:0
Average score:0

Total average score:
----------------------
Number of students:0
Average score:0

---

My current code is:
main.cpp

Code:

---

#include <iostream>
#include "student.h"
#include "calc.h"
using std::cin;
using std::cout;
using std::endl;

int main(int argc, char *argv[])
{ 
    int SEL, loop=1, x;
    klass klass1;        // Initiera ett objekt, "Klass", av klassen Klass   
    while(loop==1)
    {
        cout << "Menu selection:\n1.Add student data\n2.Randomize student data\n3.show statistics\n4.Exit" << endl;
        cin >> SEL;
        switch(SEL)
        {
            case 1:
                klass1.addstudent();
            break;
            case 2:
                cout << "not implemented yet!";
            break;
            case 3:
                klass1.collect();
                klass1.calcaverage();
                cout << "Boys average score:\n----------------------\nNumber of boys:" << klass1.numBo() << "\nAverage score:" << klass1.AvGradeBoys() << endl << endl;
                cout << "Girls average score:\n----------------------\nNumber of girls:" << klass1.numGi() << "\nAverage score:" << klass1.AvGradeGirls() << endl << endl;
                cout << "Total average score:\n----------------------\nNumber of students:" << (klass1.numGi()+klass1.numBo()) << "\nAverage score:" << klass1.averagegrade() << endl;
                cin.ignore(255,'\n');
                cin.get();
            case 4:
                return 0;
            default:
                cout << "ERROR" << endl;
        }
    }
        /*klass1.collect();
        klass1.calcaverage();
        cout << "Boys average score:\n----------------------\nNumber of boys:" << klass1.numBo() << "\nAverage score:" << klass1.AvGradeBoys() << endl << endl;
        cout << "Girls average score:\n----------------------\nNumber of girls:" << klass1.numGi() << "\nAverage score:" << klass1.AvGradeGirls() << endl << endl;
        cout << "Total average score:\n----------------------\nNumber of students:" << (klass1.numGi()+klass1.numBo()) << "\nAverage score:" << klass1.averagegrade() << endl;
        */
    cin.ignore(255,'\n');
    cin.get();
    return 0;
}

---

calc.cpp

Code:

---

#include "calc.h"
#include "student.h"
using namespace std;


klass::klass() : numG(0), numB(0), AvGradeG(0), AvGradeB(0), totGrade(0), numofstud(0), Ggrade(0), Bgrade(0)
{
}

klass::~klass()
{
}

void klass::collect()
{       

        for(int i=(numG+numB);i>0;i--)
        {
                if(getGender())            // om getGender() är sann = tösabete...
                {
                        Ggrade=Ggrade+getGrade();
                        numG++;
                }

                else                        // ...annars en hane
                {
                        Bgrade=Bgrade+getGrade();
                        numB++; 
                }
        }
}


void klass::calcaverage()
{
        if(numG>0)                      // Inte dela med noll
                AvGradeG=Ggrade/numG;

        if(numB>0)                      // inte dela med noll
                AvGradeB=Bgrade/numB;

        if((numB+numG)>0)              // inte dela med noll
                totGrade=(Bgrade+Ggrade)/(numB+numG);
}

float klass::AvGradeGirls()        // medelbetyg för tjejer
{
        return AvGradeG;
}

float klass::averagegrade()        // medelbetyg
{
        return totGrade;
}

int klass::totalStudents()
{
    return numG+numB;
}


float klass::AvGradeBoys()          // medelbetyg för killar
{
        return AvGradeB;
}

int klass::numBo()                  //  Antal B
{
        return numB;
}

int klass::numGi()                  // Antal G
{
        return numG;
}

void klass::addstudent()
{
        stud[numofstud].setGender();
        stud[numofstud].giveGrade();
    numofstud++;
}

---

student.cpp

Code:

---

#include "student.h"
using namespace std;
// Funktioner

void student::setGender()        // FALSE=boy, TRUE=girl
{ 
    bool done = false;
    while (!done)
    {
        int num;
        std::cout << "Specify sex of student; 1 (girl) or 0 (boy): ";
        std::cin >> num;
        switch( num )
        {
            case 0:
                gender = false;
                done = true;
                break;
            case 1:
                  gender = true;
                  done = true;
                  break;
              default:
                  std::cout << "You must enter 0 or 1: " << endl;
        }
    }
}

void student::giveGrade()
{
    std::cout << "Specify student grade: (1-5) ";
    std::cin >> grade;
}

float student::getGrade()
{
        return grade;
}

bool student::getGender()
{
        return gender;
}

---

calc.h

Code:

---

#ifndef CALC_H
#define CALC_H
 
#include"student.h"
#define students 20




class klass : public student
{
public:

    klass();
    virtual ~klass();
    float AvGradeGirls();      //{return AvGradeG;} medelbetyg för tjejer
    float averagegrade();      //{return totGrade;} medelbetyg
    float AvGradeBoys();      //{return AvGradeB;}  medelbetyg för killar
    void addstudent();
    int numBo();              // Antal B
    int numGi();              // Antal G
    int totalStudents();      // Totala antalet studneter
    void collect();
    void calcaverage();


private:

    student stud[students];
    int Ggrade;
    int Bgrade;                // Tjejsor och killsars sammanlagda betyg (ej  medelvärde)
    int numofstud;
    int numG;
    int numB;
    double AvGradeB;          // Gossars betyg
    double AvGradeG;          // Flickors betyg
    double totGrade;          // Totala betyget
};

#endif // CALC_H

---

student.h

Code:

---

/* Skapar elever, tilldelar dem kön samt betyg */
   
   
#ifndef STUDENT_H
#define STUDENT_H
   
#include <iostream>
   
using std::cin;
using std::cout;
   
class student
{
public:
   
    //student();
    //~student();
    void setGender();      // FALSE=boy, TRUE=girl
    void giveGrade();
    float getGrade();      //{return grade;}
    bool getGender();      //{return gender;}
   
private:
 
    bool gender;
    double grade;
};
   
#endif // STUDENT_H

---