sorry for troubling you guys again..
consider the follow part:
var choice : integer;
If choice = 1 then
var store_choice : integer;
If store_choice = 1 then
excuse me, may i ask if set the program as shown above.
when the menu procedure executes, i choose 1 to enter the "store"
then, I choose "menu" at store, would error happened?
i.e. would two procedures execute at the same time?