constructors and inheritance

anyone have any idea what this error message could mean?
I have a class Person that inherits from another class Name.
Person class does not have a constructor. Name has a constructor.
Im not sure if im doing it correclty..
Name constructor takes a few parameters like so..

Code:

---

Name(char * firstname, char * middlename, char * surname)

---

Wheni create a new person object i want to do something like

Code:

---

Person jack("jack","ant","smith");

---

error: base 'Person' with only non-default constructor in class
without a constructor
?

if i have
Name.h

Code:

---

class Name {
enum State { Teen, Child, Adult, Senior };
Name(char * firstname, char * surname, Name::State status);
~Name(void);
virtual void getAddress(void);

---

Person.h

Code:

---

#include "Name.h"
class Person: public Name {
Person(char *first, char *surname,Name::State status) : Name(first,surname,status) {}

---

main.cpp

Code:

---

#include "Person.h"
Person p("jack", "smith",State::Child);

---

why do i get hte following errors?

Code:

---

/tmp/ccwoDlOf.o(.gnu.linkonce.t._ZN9PersonC1EPKcS1_N7State4statusE+0x1f): In function `Person::Person[in-charge](char const*, char const*, State::status)':
: undefined reference to `vtable for Person'
collect2: ld returned 1 exit status
make: *** [main] Error 1

---

??

I haven't made any tests. But as i can see your constructor of name is private. That means nobody can "directly" construct an instance of this class. Is this really what you want ?

mfg JJ

hrm well after i've put

Code:

---

class Name {
public:
enum State { Teen, Child, Adult, Senior };
Name(char * firstname, char * surname, Name::State status);
~Name();

---

still same stuff happens

In your main.cpp you can't do

Person p("jack", "smith",State::Child);

Because State is not a known type. You need to use Name::State::Child

Also you need to fill out your name destructor and virtual function.

Quote:

---

Also you need to fill out your name destructor and virtual function.

---

what do you mean?

if i do
Name jac("jack", "smith",State::Child);
this works
so how come me doing
Person p("jack", "smith",State::Child);
wont work ?

This compiles okay for me.

Code:

---


#include <iostream>
using namespace std;
class Name
{
public:
  enum State { Teen, Child, Adult, Senior };
  Name(){};
  Name(char * firstname, char * surname, State status);
 
  virtual void getAddress(void){};
  char fn[80];
  char sn[80];
  State status_;
};
Name::Name(char * firstname, char * surname, State status)
{
  strcpy(fn, firstname);
  strcpy(sn, surname);
  status_ = status;
}

class Person: public Name
{
public:
  Person(char *first, char *surname, State status) : Name(first,surname,status)
  {};
  void getAddress(void){};
};
int main()
{
  Person p("jack", "smith", Name::Child);
  return 0;
}

---

The reason for the changes were:
1) as a nested type within Name, the compiler can look within Name for the declaration of the type State and figure out what

State status

means without using the scope resolution operator. However,

2) in main() the compiler can't tell where or what State is because it's buried in Name. Therefore, if I tell the compiler to look in Name for a variable called Child by using the scope resolution operator, it can resolve the type of Child to the appropriate type called State, and everybody's happy. And:

3) I added a getAddress() to Person so it had it's own version of the virtual function in Name.

Or, at least I think that's why it compiled okay.

yes your code works,
but when i follow the same structure, and place it into my seperate files
Name.cpp Name.h Person.h Person.cpp Main.cpp
it all dies..
and i get the same error message mentioned above

ok could someone check it?

this is PERSON.h

Code:

---

#ifndef _PERSON_H_
#define _PERSON_H_
#include "Name.h"
using namespace std;
class Person: public Name
{
public:
  Person(char *first, char *surname, State status) : Name(first,surname,status)
  {};
  void getAddress(void){};
};
#endif

---

this is PERSON.CPP

Code:

---

#include "Person.h"
#include "Name.h"
using namespace std;
void Person::getAddress(void) {
//nothing yet
}

---

this is NAME.h

Code:

---

#ifndef _NAME_H_
#define _NAME_H_
#include <iostream>
using namespace std;
class Name
{
public:
  enum State { Teen, Child, Adult, Senior };
  Name(){};
  Name(char * firstname, char * surname, State status);
 
  virtual void getAddress(void){};
protected:
  char fn[80];
  char sn[80];
  State status_;
};
#endif

---

This is NAME.cpp

Code:

---

#include "Name.h"
using namespace std;
Name::Name(char * firstname, char * surname, State status)
{
  strcpy(fn, firstname);
  strcpy(sn, surname);
  status_ = status;
}

---

this is MAIN.cpp

Code:

---

#include "Name.h"
#include "Person.h"
int main()
{
  Person p("jack", "smith", Name::Child);
  return 0;
}

---

and hte error is

Code:

---

/tmp/ccwoDlOf.o(.gnu.linkonce.t._ZN9PersonC1EPKcS1_N7State4statusE+0x1f): In function `Person::Person[in-charge](char const*, char const*, State::status)':
: undefined reference to `vtable for Person'
collect2: ld returned 1 exit status
make: *** [main] Error 1

---

First off, the getAddress is declared inline and in the .h file...

*Had to leave, sorry for no big description*

(now that I think of it, the inline, I don't think, would be a problem)

This organizational pattern and code compiles without error in MSVC 6.0. It doesn't do anything. But that's beside the point.

Code:

---

//Name.h
#ifndef NAME_H
#define NAME_H
class Name
{
public:
        enum State { Teen, Child, Adult, Senior };
        Name(){};
        Name(char * firstname, char * surname, State status);
 
        virtual void getAddress(void){};
 
        char fn[80];
        char sn[80];
        State status_;
};
#endif

---

Code:

---

//Name.cpp
#include "Name.h"
#include <cstring>
Name::Name(char * firstname, char * surname, State status)
{
  strcpy(fn, firstname);
  strcpy(sn, surname);
  status_ = status;
}

---

Code:

---

//Pearson.h
#ifndef PEARSON_H
#define PEARSON_H
#include "Name.h"
class Person: public Name
{
        public:
        Person(char *first, char *surname, State status) : Name(first,surname,status)
                {};
        void getAddress(void){};
};
#endif
 
//there is no Pearson.cpp since all constructors methods in Pearson.h are inlined given their simplicity

---

Code:

---

//driver.cpp
#include <iostream>
#include "Pearson.h"
using namespace std;
int main()
{
  Person p("jack", "smith", Name::Child);
  return 0;
}

---

thanks