C++ : Assign normal return value to a pointer

How do I assign a normal return value of a function to a pointer?

For example, I want to assign the return value of this static member function:

int AnotherClass::getInt();

In the following expression :

// m_ipA is a private member of the class `Class`
int *m_ipA;
// Lots of things in between, then :
void Class::printOutput() {
    m_ipA = AnotherClass::getInt();
    // Some operations on m_iPA here, then
    // Print instructions here
}

Do I need to initialize m_ipA with the new keyword in t开发者_如何学运维he constructor?

Thanks in advance.

If m_ipA is not pointing to any valid memory location then you need to allocate memory like following:

m_ipA = new int(AnotherClass::getInt());

Do this:

 m_ipA = new int; //do this also, if you've not allocated memory already.
*m_ipA = AnotherClass::getInt();

You may want to allocate memory in the constructor of the class as:

Class::Class() //constructor
{
  m_ipA = new int; //allocation
}

void Class::printOutput() 
{
    *m_ipA = AnotherClass::getInt();
}

Class::~Class() //destructor
{
  delete m_ipA; //deallocation
}

EDIT:

As MSalters reminded: when you've pointers in your class, then don't forget the copy ctor and assignment (Rule of Three).

Or mabye, you don't want pointer to int. I mean, the following might work for you:

int m_int; 

m_int = AnotherClass::getInt(); 

Notice m_int is not a pointer.

m_ipA = new int;
*m_ipA = AnotherClass::getInt();

//Use m_ipA

delete m_ipA; //Deallocate memory, usually in the destructor of Class.

Or use some RAI such as an auto_ptr. To forget about deallocating memory.

No, you don't have to - just make sure you dereference the pointer!

*m_ipA = AnotherClass::getInt(); You really should though, if you intend to continually modify m_ipA