DECLARE SUB cprint (t$)
DECLARE SUB DisplayIntro ()
DECLARE SUB initialize (F() AS ANY)
DECLARE SUB Move1To2 (F() AS ANY)
DECLARE SUB Move2to1 (F() AS ANY)
DECLARE SUB DisplayProportions (F() AS ANY, t)
SCREEN 9

WINDOW SCREEN (0, 0)-(12, 2)
VIEW (100, 100)-(600, 300)

LINE (0, 0)-(12, 2), 15, BF
LINE (0, 0)-(12, 2), 4, B
LINE (0, 1)-(12, 1), 4

TYPE AFish
pond AS INTEGER
col AS INTEGER
END TYPE
CONST NumFish = 2300
DIM Fish(NumFish) AS AFish


initialize Fish()
DisplayIntro
DO
Move1To2 Fish()
Move2to1 Fish()
ct = ct + 1
DisplayProportions Fish(), ct / 100


LOOP

SUB Comment (t$)
'print comments while program executes
BEEP
COLOR 2, 0
cs = CSRLIN
ps = POS(1)
PRINT "Comment: ";
PRINT t$
PRINT "Press any key to continue..."
WHILE INKEY$ = ""
WEND
cs2 = CSRLIN
COLOR 7, 0
LOCATE cs, ps
FOR j = cs TO cs2
PRINT SPACE$(80)
NEXT j
LOCATE cs, ps
END SUB

SUB cprint (t$)
'center print
l = 41 - LEN(t$) \ 2
IF l < 1 THEN l = 1
LOCATE , l
PRINT t$
END SUB

SUB DisplayIntro
LOCATE 10, 1
PRINT "Small Pond"
LOCATE 18, 1
PRINT "large Pond"
LOCATE 1, 1
cprint "This is a simulation of transfering fish"
cprint "The large pond has 50% black fish"
cprint "The small pond has 100% black fish"
cprint "Poportion of black fish in each pond is graphed as tranfers occur"
END SUB

SUB DisplayProportions (F() AS AFish, t)
'display contents of ponds
STATIC x1
STATIC x2
STATIC t1
n = UBOUND(F)
DIM Black(2), pond(2)
FOR j = 1 TO n
IF F(j).col = 0 THEN Black(F(j).pond) = Black(F(j).pond) + 1
pond(F(j).pond) = pond(F(j).pond) + 1
NEXT j
y1 = Black(1) / pond(1)
y2 = Black(2) / pond(2)
LOCATE 11, 1
PRINT y2
LOCATE 19, 1
PRINT y1
LINE (t1, 2 - x1)-(t, 2 - y1), 2
LINE (t1, 1 - x2)-(t, 1 - y2), 2
t1 = t
x1 = y1
x2 = y2

END SUB

SUB initialize (Fish() AS AFish)
'initialize colors and ponds

FOR j = 1 TO 2200
Fish(j).pond = 1
Fish(j).col = (j MOD 2)
NEXT j
FOR j = 2200 TO 2300
Fish(j).pond = 2
Fish(j).col = 0
NEXT j
END SUB

SUB Move1To2 (F() AS AFish)
'move a fish at random from Pond 1
'just try fishing
n = UBOUND(F)
k = INT(RND * n + 1)
WHILE F(k).pond = 2
k = INT(RND * n + 1)
WEND
F(k).pond = 2

END SUB

SUB Move2to1 (F() AS AFish)
'move a fish at random from Pond 2
'just try fishing
n = UBOUND(F)
k = INT(RND * n + 1)
WHILE F(k).pond = 1
k = INT(RND * n + 1)
WEND
F(k).pond = 1
END SUB

SUB shuffle (Deck())
'Shuffle the deck of cards
n = UBOUND(Deck)
ns = n
FOR j = 1 TO n
'take a card at random and put it away
k = INT(RND(1) * ns + 1)
SWAP Deck(k), Deck(ns)
ns = ns - 1
NEXT j
END SUB