Returning a refrence from a function

Abhishek Narula

Hi there , I have a class lets say CMyClass, it contains a member variable of type CArray of lets say int. Now I have a public function of this Class GetValue(int nIndex) now this function returns the Reference of int which is actually a reference to a particular index of my CArray type member variable. Now here is the problem .. My GetValue function performs some checks before returning the Refrence . now in case the checks fails I dont want to return the reference .. in that case WHAT DO I RETUNR FROM MY CODE. does any body understand what I am trying to ask ? Abhishek Narula "Learn to appreciate others ... World would appreciate you"

Joaquin M Lopez Munoz

Throw an exception. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

markkuk

Throw an exception. There's no reference equivalent of a NULL pointer, so you must either return a valid reference or throw.

Abhishek Narula

Hmm that seems a better idea .. please throw some light on thoring exceptions also .. Abhishek Narula "Learn to appreciate others ... World would appreciate you"

Abhishek Narula

Wonderfull Idea !! thanks .. please tell me more about throwing exceptions also .. Abhishek Narula "Learn to appreciate others ... World would appreciate you"

Joaquin M Lopez Munoz

Essentially, you just throw with throw, which interrupts the normal flow of execution and throws an object that can be catched by some point up the call stack with catch. Just read your docs for throw and catch, and/or search some tutorial on the net, sure there're many out there. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

Alexandru Savescu

It goes like this: 1. Create a class CMyException. Here is an example:

class CMyException
{
CString strError;
public:
CMyException (CString& a) : strError (a) {}
void HandleError ()
{
AfxMessageBox (strError);
}
}

2. Do this in that function:

if (index_is_out_of_bounds)
throw CMyException ("Index out of bounds"); // throw the exception

3. Catch the exception like this:

try
{
// call the function that may throw the exception
}
catch (CMyException& e)
{
// caught an exception and now handle it
e.HandleError ();
return;
}

You can also check MSDN for details or download a good C++ book. "Thinking in C++" from www.bruceeckel.com Best regards, Alexandru Savescu