Trouble with inheritance.....

This is a discussion on Trouble with inheritance..... within the C++ Programming forums, part of the General Programming Boards category; Hi all, I'm writing a program which uses inheritance but it won't compile! I believe the constructor of the base ...

  1. #1
    Registered User JM1082's Avatar
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    Unhappy Trouble with inheritance.....

    Hi all,

    I'm writing a program which uses inheritance but it won't compile! I believe the constructor of the base class is to blame, but I'm not sure as I've not had much experience with inheritance.

    Please find 5 of my code files attached ( 5 is maximum allowed ) and the last 2 below for perusal.

    Code:
    // userControlledCharacterClass.h
    #ifndef USERCONTROLLEDCHARACTERCLASS_H
    #define USERCONTROLLEDCHARACTERCLASS_H
    #include "RPG.h"
    
    
    class userControlledCharacterClass: public RPG
    {
    public:
        userControlledCharacterClass(); // constructor
        userControlledCharacterClass( string, string, int, int, int, int ); // constructor
        ~userControlledCharacterClass(); // destructor
    protected:
    private:
    };
    
    #endif // USERCONTROLLEDCHARACTERCLASS_H
    Code:
    // userControlledCharacterClass.cpp
    #include "userControlledCharacterClass.h"
    using namespace std;
    
    userControlledCharacterClass::userControlledCharacterClass()
    {
    
    } // end constructor userControlledCharacterClass
    
    userControlledCharacterClass::userControlledCharacterClass( string a, string b, int c, int d, int e, int f )
    {
        setName( a );
        setDescription( b );
        setXP( c );
        setHP( d );
        setAP( e );
        setLocation( f );
    } // end constructor userControlledCharacterClass
    
    userControlledCharacterClass::~userControlledCharacterClass()
    {
        cout << getName() << " has died!1" << endl;
    } // end destructor ~userControlledCharacterClass()
    Attached Files Attached Files

  2. #2
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by JM1082
    I'm writing a program which uses inheritance but it won't compile!
    What is the exact error message, and where is it detected?
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  3. #3
    Registered User JM1082's Avatar
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    Detected in line: 5 & 10 of userControlledCharacterClass.cpp
    Error message reads: Undefined reference to RPG::RPG()

    Strangely, this error is detected twice at each line.....

  4. #4
    C++ Witch laserlight's Avatar
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    You forgot to define the default constructor for RPG.
    C + C++ Compiler: MinGW port of GCC
    Version Control System: Bazaar

    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  5. #5
    Registered User JM1082's Avatar
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    Thanks Laserlight! Your sharp eye is only exceed by your majesty!

    However, I've two last questions!

    Is it compulsory to include a constructor with an empty arguments list?

    And, why are seven objects of each class destroyed when I've only created three?

  6. #6
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by JM1082
    Is it compulsory to include a constructor with an empty arguments list?
    No. However, if you do not have a default constructor for a base class, then the constructors of classes that derive from the base class would need to specify which base class constructor to invoke in their initialiser lists.

    Quote Originally Posted by JM1082
    And, why are seven objects of each class destroyed when I've only created three?
    Maybe you did not notice that you were doing some copying.

    Off topic: I just heard that Barbara Liskov, after whom the Liskov substitution principle is named, is in Singapore right now giving a talk at my alma mater. Pity I am unable to attend.
    C + C++ Compiler: MinGW port of GCC
    Version Control System: Bazaar

    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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