Programming Forums > Application Development > C++

-=PARADOX=- · Nov 24th, 2005, 9:59 AM

Hi there again

I have one annoying problem here :eek:

I have one class 'CVector':

class CVector
{
        int *vector;
        unsigned n;   // this is the number of elements
public:
        CVector( );
        CVector( unsigned );
        virtual ~CVector();

         int& operator[] ( const int );
         const int& operator[] ( const int ) const;



};

And one 'CMatrix' derived from that:

(Toggle Plain Text)

class CMatrix : public CVector
{
        CVector *matrix;
        unsigned lin, col;
        string m_sNome;
public:
        CMatrix( const string&, const unsigned, const unsigned );
        ~CMatrix();

        CVector& operator[] ( const int );
        const CVector& operator[] ( const int ) const;
        friend CMatrix operator*( const CMatrix&, const CMatrix& );
};

Now in the constructor of CMatrix, i need to reserve dynamic memory for the array of CVector's, but I want each CVector inicialized with 'c' colums so I do this:

(Toggle Plain Text)

CMatrix( const string& str, const unsigned l, const unsigned c)
      lin( l ), col( c ), m_sNome( str )
{
        matrix = new CVector[ l ];
}

But if i do this, the each CVector object in the array is not incialized with c colums...

How can I do this???

Thanks in advance

robrosas · Nov 24th, 2005, 11:04 AM

I only made a fast overview of your code but I can see that you can solve your problem by initializing every CVector object in the matrix object with some loop. Like a for loop .

(Toggle Plain Text)

 for (int i =0;i< matrix array size ;i++) {
 matrix[i]= new CVector(c);
}

That should be in the constructor.

ivan · Nov 24th, 2005, 11:17 AM

nice first post..

-=PARADOX=- · Nov 24th, 2005, 3:16 PM

That makes sence :p

I'll try it

Thank you very nice

grumpy · Nov 25th, 2005, 3:48 AM

Unrelated to the problem, I know, but what is actually being achieved by deriving CMatrix from CVector?

-=PARADOX=- · Nov 25th, 2005, 4:53 AM

I guess nothing...

robrosas · Nov 25th, 2005, 8:42 AM

I saw that too grumpy, but he only asked for the constructor problem. Theres no sense why should CMatrix derives from Cvector. CMatrix can simply just "use" a Cvector and that's it.

-=PARADOX=- · Nov 25th, 2005, 8:46 AM

Ye you are right

Nov 24th, 2005, 9:59 AM	#1
-=PARADOX=- Programmer Join Date: Oct 2005 Location: Portugal Posts: 53 Rep Power: 3	Matrix Hi there again I have one annoying problem here :eek: I have one class 'CVector': (Toggle Plain Text) class CVector { int vector; unsigned n; // this is the number of elements public: CVector( ); CVector( unsigned ); virtual ~CVector(); int& operator[] ( const int ); const int& operator[] ( const int ) const; }; class CVector { int vector; unsigned n; // this is the number of elements public: CVector( ); CVector( unsigned ); virtual ~CVector(); int& operator[] ( const int ); const int& operator[] ( const int ) const; }; And one 'CMatrix' derived from that: (Toggle Plain Text) class CMatrix : public CVector { CVector matrix; unsigned lin, col; string m_sNome; public: CMatrix( const string&, const unsigned, const unsigned ); ~CMatrix(); CVector& operator[] ( const int ); const CVector& operator[] ( const int ) const; friend CMatrix operator( const CMatrix&, const CMatrix& ); }; class CMatrix : public CVector { CVector matrix; unsigned lin, col; string m_sNome; public: CMatrix( const string&, const unsigned, const unsigned ); ~CMatrix(); CVector& operator[] ( const int ); const CVector& operator[] ( const int ) const; friend CMatrix operator( const CMatrix&, const CMatrix& ); }; Now in the constructor of CMatrix, i need to reserve dynamic memory for the array of CVector's, but I want each CVector inicialized with 'c' colums so I do this: (Toggle Plain Text) CMatrix( const string& str, const unsigned l, const unsigned c) lin( l ), col( c ), m_sNome( str ) { matrix = new CVector[ l ]; } CMatrix( const string& str, const unsigned l, const unsigned c) lin( l ), col( c ), m_sNome( str ) { matrix = new CVector[ l ]; } But if i do this, the each CVector object in the array is not incialized with c colums... How can I do this??? Thanks in advance

Nov 24th, 2005, 11:04 AM	#2
robrosas Newbie Join Date: Nov 2005 Location: Puerto Rico Posts: 12 Rep Power: 0	Let me see.. I only made a fast overview of your code but I can see that you can solve your problem by initializing every CVector object in the matrix object with some loop. Like a for loop . (Toggle Plain Text) for (int i =0;i< matrix array size ;i++) { matrix[i]= new CVector(c); } for (int i =0;i< matrix array size ;i++) { matrix[i]= new CVector(c); } That should be in the constructor. __________________ From P.R. to the World!! RoBeRt Last edited by robrosas; Nov 24th, 2005 at 11:05 AM. Reason: forgot something

Nov 25th, 2005, 8:42 AM	#7
robrosas Newbie Join Date: Nov 2005 Location: Puerto Rico Posts: 12 Rep Power: 0	... I saw that too grumpy, but he only asked for the constructor problem. Theres no sense why should CMatrix derives from Cvector. CMatrix can simply just "use" a Cvector and that's it. __________________ From P.R. to the World!! RoBeRt

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Nov 24th, 2005, 11:17 AM	#3
ivan Professional Programmer Join Date: Sep 2005 Location: serbia & montenegro Posts: 484 Rep Power: 3	nice first post..

Nov 24th, 2005, 3:16 PM	#4
-=PARADOX=- Programmer Join Date: Oct 2005 Location: Portugal Posts: 53 Rep Power: 3	That makes sence :p I'll try it Thank you very nice

Nov 25th, 2005, 3:48 AM	#5
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,198 Rep Power: 5	Unrelated to the problem, I know, but what is actually being achieved by deriving CMatrix from CVector?

Nov 25th, 2005, 4:53 AM	#6
-=PARADOX=- Programmer Join Date: Oct 2005 Location: Portugal Posts: 53 Rep Power: 3	I guess nothing...

Nov 25th, 2005, 8:46 AM	#8
-=PARADOX=- Programmer Join Date: Oct 2005 Location: Portugal Posts: 53 Rep Power: 3	Ye you are right

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)