C / C++ / MFC

failfunc(); // would normally actually do something
       char *mystr = new char[512]; // something in the try block determines the size needed, so must
                                       be allocated in the try block
       Statement 1.....
       delete [] mystr;

//
// Smart pointer class for arrays
//
template< typename T >
class ArrayPtr
{

public:

    ArrayPtr( T* pointee )
        : _pointee( pointee )
    {
    }

    inline ~ArrayPtr() {
        if( _pointee )
            delete[] _pointee; // Array destruction
    } 

    operator T*() {
        return _pointee
    }

    // ... more needed here. Just google smart pointers.
    // Basically you need operator->, operator*, but not operator&
    // plus assignment etc.

private:

    T* _pointee;

};

//
// How to use it in your example
//
void failfunc()
{
    throw 1; // obviously not practical, just for example
}

void main()
{
    try {
        ArrayPtr< char > mystr( new char[512] ); // Freed automatically when mystr goes out of scope or an exception is thrown
        failfunc();
    } catch( int err ) {
        // Tell the user something went wrong
        std::cerr << "Error #" << err << std::endl;
    }
}

template< typename T > class ArrayPtr { /*... see above*/ };

void failfunc() { /*... see above*/ }

void main()
{
    ArrayPtr< char > mystr( new char[512] ); // Freed automatically when mystr goes out of scope or an exception is thrown
    failfunc();
}