Write an Append() function that takes two lists, 'a' and 'b', appends 'b' onto the end of 'a', and then sets 'b' to NULL (since it is now trailing off the end of 'a').
When playing with pointers (and linked lists), you should always get out some paper and a pencil and draw what you have, then modify the drawing to show what you want to have happen, and make your code do the same thing you had to do with your pencil and eraser.