From the previous figure, it is clear that cardsleft must have been assigned a zero before line 60. To see the source code that did this, we have to scroll the source code window back.
(dbxtra) backwardThe backward command scrolls the source window back one full window. To scroll the window forward to see again how cardsleft is used, we use the command forward.
Typing these screen motion commands in full each time is tedious, so dbxtra provides the alias command to rename commands. For example, to rename the backward command to b, for example, type:
(dbxtra) alias b backwarddbxtra provides a set of default aliases. To view them, type alias itself at the
Having moved back one screen, we see that cardsleft is a parameter of Deal(). Therefore, to see how it was passed the value zero, we have to find out which function called it. This can be done by looking at the call stack.