Merge pull request #892 from GKnirps/king_tourist_bug

Add documentation for tourist trade bug in King

53_King/README.md

@@ -78,3 +78,18 @@ On basic line 1310 we see this:
 but it should probably be:
 
     1310 IF J=0 THEN 1324
+
+### Bug 5
+
+On basic line 1390 the income from tourism is calculated:
+
+```
+1390 A=INT(A+Q)
+1400 V1=INT(((B-P1)*22)+(RND(1)*500))
+1405 V2=INT((2000-D)*15)
+1410 PRINT " YOU MADE";ABS(INT(V1-V2));"RALLODS FROM TOURIST TRADE."
+```
+
+It is very easily possible that `V2` is larger than `V1` e.g. if all of the land has been sold. In the original game this does not make a difference because of Bug 1 (see above).
+
+However, judging by how `V1` and `V2` are handled in the code, it looks like `V1` is the basic income from tourism and `V2` is a deduction for pollution. When `ABS(INT(V1-V2))` is used as earnings from tourism, the player actually _gets_ money for a large enough pollution. So a better solution would be to let `V1 - V2` cap out at 0, so once the pollution is large enough, there is no income from tourists anymore.

53_King/python/king.py

@@ -61,7 +61,7 @@ class GameState:
         return self.countrymen - self.population_change
 
     def sell_land(self, amount: int) -> None:
-        assert amount < self.farmland
+        assert amount <= self.farmland
         self.land -= amount
         self.rallods += self.land_buy_price * amount
 
@@ -126,7 +126,9 @@ class GameState:
     def handle_tourist_trade(self) -> None:
         V1 = int(self.settled_people * 22 + random() * 500)
         V2 = int((INITIAL_LAND - self.land) * 15)
-        tourist_trade_earnings = int(V1 - V2)
+        tourist_trade_earnings = 0
+        if V1 > V2:
+            tourist_trade_earnings = V1 - V2
         print(f" YOU MADE {tourist_trade_earnings} RALLODS FROM TOURIST TRADE.")
         if V2 != 0 and not (V1 - V2 >= self.tourism_earnings):
             print("   DECREASE BECAUSE ")