Second Iteration

Rather than beginning to code the actual functions, we may want to double check that the ``flow" of our program is as we expect it. We may write a ``dummy" versions of the more difficult parts of the program, and test its operation. Only after we are sure that the program behaves as expected, we can invest more time into coding more difficult parts.

Here is a test program. It was produced from the previously described code; all newly added parts are clearly marked so that they can be removed once not needed.

DEF TYPE Cards
'***test***
REM Suite as string
Suite as integer
'*** end test ***
Value as integer ' we may want string here, too!
End type

Dim Shared Deck(52) as cards
DIM Shared Order(52)

InitializeDeck
ShuffleDeck
'ask first player
n=HowManyCards
DealCards(n)
'ask second player
n=HowManyCards
DealCards(n)

SUB InitializeDeck
'Initialize cards to their values.
'*** test ***
for j = 1 to 52
Deck(j).value=j mod 13 +1
Deck(j).suit=j mod 4 +1
next j
'*** end test ***
END SUB

SUB ShuffleDeck
'Make a random permutation
'Store it in Order()
'Order(1), Order(2) are distinct random numbers range 1,...n,
'*** test ***
'Factory order
For j= 1 to 52
Order(j)=j
NEXT j
'*** end test ***
END SUB

FUNCTION HowManyCards%
' Ask user how many cards (s)he requests
' store in variable.
' Check how many cards are left
' Print out Error message if not enough cards
' return value if enough cards are left.
'*** test ***
INPUT ``How many cards"; x
' should check for "crazy" answers here
HowManyCards=x
'*** end test ***
END FUNCTION

SUB DealCards(n)
' Remember how many cards are left
'Print next n cards
'*** test ***
' just print first n cards for now
Print "Your cards are:"
FOR j=1 TO n
Print Deck(Order(j)).Value ; " of suit No" ;Deck(Order(j)).Suit
NEXT j
'*** end test ***
END SUB

With this ``skeleton" program we can check the following things:

1. Does the program do what we wanted? Are shared variables shared between subprograms?
2. Are there any preliminary coding mistakes/typos? Are the variables of correct type (as declared in each SUB/FUNCTION)?
3. Does the output routine operate correctly? (Ask for various numberst of cards. Reverse the order in SUB ShuffleDeck.)