ATL / WTL / STL

int OnlyLeafNodes(Elem *t, int currentDepth=0)
{
	// if 'this' is null, return
	if(!t) 
		return currentDepth;

	// inc the depth because we represent another one
	currentDepth++;

	// ask each of the children, how deep they go, relative to me
	int leftDepth=OnlyLeafNodes(t->left,currentDepth)-currentDepth);
	int rightDepth=OnlyLeafNodes(t->right,currentDepth)-currentDepth);

	// spots 1,1 | 1,0 | 0,1
	if(max(leftDepth,rightDepth)==1)
		cout << t->key << endl;  

	// and return the depth this node represents
	return currentDepth;
}

#define max(a,b) a>b?a:b

// and return the depth this node represents
return currentDepth+(maxDepth,rightdepth);

return currentDepth - leftDepth + rightDepth;

// and return the depth this node represents
return currentDepth+max(leftDepth,rightdepth)

OnlyLeafNodes(rootNode,0);

boost::tmatch what;
 
if(boost::regex_match(path, what, r))

void Go()
{
	try
	{
		CString path = _T("abcd");
		static const boost::tregex r(_T("*bc"));
		boost::tmatch what;
	 
		if(boost::regex_match(path, what, r))
		{
		}
		else
		{
		}
	}
	catch (const boost::regex_error &e)
	{
		cout << e.what() << endl;
		throw;
	}
}

The repeat operator "*" cannot start a regular expression.  The error occured while parsing the regular expression: '>>>HERE>>>*bc'.