Thread: Objects

Hi,
How can we delete the objects initialised by the pointers automatically in a program without delete[]/delete keyword. Like for example java explicitly runs the garbage collector. Can we do that same way somehow??
thank you.

No, in C/C++ you don't have a garbage collector. In these languages you have to do most of the stuff by yourself. That's why they're so powerful (and not very good for begginers).
Although I think there is some third-party code you can add to your app to make a sort of garbage collector, they're very slow. Wouldn't recommend it. Besides, it's a good practice to tidy up after you, even in programming.

Use something from the standard library like an auto_ptr...

Code:

#include <memory> //for auto_ptr
#include <iostream>
using namespace std;
template <class T>
ostream& operator<< (ostream& strm, const auto_ptr<T>& p)
{

  if (p.get() == NULL) 
       strm<<"NULL";
   else
     strm<<*p;
   return strm;
}

int main(void)
{
int x;
auto_ptr<int> aPtr(new int); //create an auto_ptr object and allocate mem
*aPtr=1;
cout<<aPtr<<endl; //only works with overloaded << operator 
auto_ptr<int> aPtr2(aPtr); //now aPtr2 is equal to aPtr 
cout<<aPtr<<endl; //ERROR now aPtr is deleted
cout<<aPtr2;
//the end
cin>>x; //just a quickie pause 
}

MSVC++ .NET has a garbage collector. I haven't had any problems with using it although typically I like to clean up after myself anyway.

Here is a simple garbage collector example I wrote on the C board. Unfortunately, it hasn't been compiled, so you're on your own debugging-wise. But the basic concept is simple:

1) store the address of the pointer.
2) store the data that the said pointer points to.

ie:

char * ptr = new char[10240];
(1) char ** pa = &ptr;
(2) char * p = ptr;

So that:

if(*pa != p) delete [] p;

Of course you'll need a list or vector of these memory managers.

Also, you can set up the garbage collection in a low-priority thread, but in most cases, there's no real justification to do so.