C / C++ / MFC

_AnShUmAn_ wrote:

This is how it is done in VC7

"The largest fire starts but with the smallest spark." - David Crow

Anu_Bala wrote:

I am working in vc++ for past 4 months.But i dont know very much about MFC.That is where the variables stored and memory allocation like that.When im doing coding,i got error as unhandled exception,Out of memory like that.So, i think im unaware about the memory allocation.So, Is there any tutorial about this allocation etc.,..?

1. Use new and delete.
   
2. Always use delete[] with new[] and delete with new
3. Do not mix up c, c++. Either you use C, or use C++ for memory allocation.
   
4. Always set a pointer to NULL after deletion.
   
5. Always allocate sufficient amount of memory. Do not allocate memory like this...
   
   

   char *str = new char[ strlen( someStr ) ];//stingy
   strcpy( str, someStr );// well asking for trouble
   delete [] str;//error here
   str = NULL;//good practice

   
   instead use
   
   

   char *str = new char[ strlen(someStr) + 1 ];//bring it on
   strcpy( str, someStr );//gooood, very gooood.
   delete [] str;//hehe fine
   str = NULL;//good practice

   
   
6. Try using auto_ptr;
   
7. Maintain a list of pointers to memory that you have allocated. When you exit from your app you can delete them all at one go if any of them hasn't been deleted.
   
8. Always check for NULL on pointers after a new.
   
9. Always check for NULL on pointers before using them.
   
10. Be really really afraid to dynamically allocate memory.
    

Nibu thomas wrote:

strcpy( str, someStr );// well asking for trouble

Nibu thomas wrote:

delete [] str;//error here

Nibu thomas wrote:

Be really really afraid to dynamically allocate memory.

"The largest fire starts but with the smallest spark." - David Crow

DavidCrow wrote:

Nibu thomas wrote:
delete [] str;//error here

DavidCrow wrote:

Nibu thomas wrote:
Be really really afraid to dynamically allocate memory.


Why?

Nibu thomas wrote:

Well if you are using strcpy for that purpose strcpy will put a NULL char just after the end of the memory block.

Nibu thomas wrote:

For eg: using standard stl classes can avoid most of the issues.

"The largest fire starts but with the smallest spark." - David Crow

DavidCrow wrote:

But the point is that the source could be longer than the destination, which is why strcpy() should not be used, regardless of how it deals with the \0 terminator.

DavidCrow wrote:

Last time I checked, STL used memory from the heap (i.e., dynamic). There's just not any way around not using memory from the heap.

SaRath C wrote:

In MFC, it is not using any special allocation strategy, its all C++.

SaRath C wrote:

at our point of view, operator new has a standard form and a predefined way which it should be used. I just indicated about that fact.

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Staff Engineer<br />
<A HREF="http://www.soonr.com">SoonR Inc.</A>