Re: Where to free memory ?

From:
mzdude <jsanga@cox.net>
Newsgroups:
comp.lang.c++
Date:
Mon, 9 Nov 2009 10:15:00 -0800 (PST)
Message-ID:
<afee2b73-6c72-40ab-8dfb-e4a532893621@u13g2000vbb.googlegroups.com>
On Nov 9, 12:26 pm, Phil <pbruy...@yahoo.com> wrote:

Hello all,
I kindly request your help for the following problem.
Let's say I have two classes A and B defined as follows:

// ClassA.h //////////////////////////
class ClassA
{
public:
  void ClassA(int nItems); // constructor
  virtual ~ClassA();
protected:
  double *myTable; // My table of nItems double values

}


Even with VC6, I would use std::vector<double> myTable
and get rid of the dynamic memory issues. But if you don't...

/////////////////////////////////////

// ClassA.cpp ///////////////////////
void ClassA(int nItems)
{
  // Allocate memory for the table of double values
  myTable=(double*)calloc(nItems, sizeof(double));

}

Assume this is:
void ClassA::ClassA(int nItems)
  : myTable( (double *)calloc(..) )
{
  if( myTable == NULL )
    throw std::bad_alloc();
}

if you were using std::vector

void ClassA::ClassA(int nItems)
  : myTable(nItems,0.0)
{}

~ClassA()
{
// Should I free the memory allocated for myTable here?
// free(myTable);
// myTable=NULL;

}

Yes you should free memory here. The myTable=NULL can
be omitted.

If you are using std::vector, you don't even need the dtor.

/////////////////////////////////////

// ClassB.h //////////////////////////
#include "ClassA.h"
class ClassB
{
public:
  void ClassB();
protected:
  ClassA classA(int nItems);

This is invalid. Should just be ClassA classA;
Or given the code below
  ClassA *classA;

/////////////////////////////////////

// ClassB.cpp ///////////////////////
void ClassB()
{
classA=new ClassA(10);
// Do some processing here with classA
delete classA;

}

classA is not declared as a pointer in your example.
This should refuse to compile.

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