Heap ,Stack allocation question [Solved]

[econy]

Please read the pseudo code as follows:

class A
{
CMap myMap;
A() {
myMap.InitHashTable(857);
}
};

void test(void)
{
A *pa = new A();
}

My question is, myMap member in A class is in Heap or Stack? is destructor of A class need to delete myMap object expressly?

[Lost User]

The actual memeory used by the Map is allocated internally and dynamically, so it will be on the Heap. You may need to delete the map in your destructor, it depends on the lifetime of your object.

[econy]

So, the myMap memory allocation is dominated by it's container class A, right? for pseudo code like the following:

void test() //A global function
{
CMap myMap;

}

then I　ｄｏｎｔ　ｎｅｅｄ　ｔｏ　ｄｅｌｅｔｅ　ｍｙＭａｐ　ｅｘｐｒｅｓｓｌｙ，　ｒｉｇｈｔ？myMap should be in function stack.

[Lost User]

That is correct, as far as I recall; MFC classes clean up after themselves.

[econy]

I try to use delete myMap, IDE shows cannot convert from 'CMap' to 'Void*'.

[Lost User]

You need to show us your code, we cannot guess what you have done.

[econy]

class A
{
private:
A m_Map;
public :
A();
~A();
};

//Constructor
A::A()
{
m_Map.InitHashTable(MAP_LEN);
}

A:~A()
{
delete m_ConfigMap; //This statement triggered error message
}

error C2440: 'delete' : cannot convert from 'CMapStringToString' to 'void *'

[Richard Andrew x64]

I see two issues here: 1. Where is m_ConfigMap declared? 2. You have m_Map declared as an A. Is that what you meant?

The difficult we do right away... ...the impossible takes slightly longer.

[econy]

sorry, yes, m_configMap should be m_Map.

[Lost User]

That code makes no sense. You declare m_Map as an object of class A. You then try to call InitHashTable on it in the constructor, even though that function is not declared anywhere. Finally you try to delete m_ConfigMap which also is not declared anywhere.