returning address of local variable or temporary

[curious2007]

Hello Everyone,

I had this code working on DEV C++. But now, it does not work in Visual C++ Exress. Here is the code:

template <class V, class AI, class I, class S> 
   const V& AssocArray<V, AI, I, S>::operator [] (const AI& index) const
{
    const_iterator it = internal_array.find(index);
 
    V mapIndex = (*it).second;
    return mapIndex;
 
}

I get the following warning:

warning C4172: returning address of local variable or temporary

It is not clear to me what this means. I would appreciate any help.

[sicarie]

Please make sure you use code tags (they're in the box to the right when you are creating/replying to a thread.

[Darryl]

The error is right, you are returning a local/temp variable. Why don't you return (*it).second; directly?

[curious2007]

OK, thanks. Do you know why is this a reason for warning?

[Darryl]

OK, thanks. Do you know why is this a reason for warning?

Because when the local variable (MapIndex in your case) goes out of scope (when the function returns) it is destroyed and therefore no longer valid.