more skeleton program

Question 1

How does the program handle invalid user input, and what happens to the game state when the user enters an invalid expression?

Answer 1

If the input is invalid, CheckIfUserInputValid() returns False, and the program deducts a point from the score.
- targetlist and numbers allowed remain unchanged

Question 2

How does the program manage the Targets list throughout the game, and what is the significance of updating and removing targets from the list?

Answer 2

• The Targets list represents the goals the player needs to achieve. Each time a target is hit, it is removed by setting it to -1
• Updating the target list allows new targets to be added, while previously hit targets are marked as completed
• This ensures that the player has new targets to reach as they progress through the game

Question 3

What is the role of the NumbersAllowed list, and how is it updated throughout the game? What happens if a user tries to use a number not in the allowed list?

Answer 3

• NumbersAllowed list represents the numbers that the user can use to form valid expressions.
• Whenever a user uses a number from this list in a valid expression, that number is removed from NumbersAllowed for the next round.
• If a user tries to use a number that is not in NumbersAllowed, the program will reject the input

Question 4

Explain the process that occurs when the game is over. How is the final score displayed, and what condition causes the game to end?

Answer 4

• The game ends when all the targets are completed, which is indicated by the first target being set to -1.
• When this condition is met, GameOver is set to True, and the game loop terminates. The final score is then displayed using the DisplayScore() function.

Question 5

\d+
\s*
what do these do

Answer 5

/d+ - Matches one or more digits (numbers).

• \s* → Matches zero or more spaces (this allows spaces but doesn’t require them).

Question 6

what does “r” before a string do eg:|re.search(r”^(\d+\s[+-*/]\s)+\d+$”, UserInput)

Answer 6

With a raw string, Python treats backslashes as normal characters, so we don’t need to double them.
- without them, we would have to write

re.search(“^(\d+\s[\+\-\/]\s*)+\d+$”, UserInput)

Question 7

Brackets question flow

Answer 7

Numbers → output queue
( → push on stack
) → pop until (
Operator → pop operators with higher precedence, then push
End → pop all remaining operators

ConvertToRPNWithBrackets uses a stack to handle operators and parentheses by precedence. Numbers go straight to output. ( pushes on stack, ) pops until (. Operators pop from stack if they have higher precedence than incoming operator. Finally, all operators popped to output.

Question 8

What regex pattern is used to validate the user input allowing brackets?

Answer 8

r”[0-9+-*/()]+”

Question 9

brackets question: how to grab multi-digit numbers (\d+) or any single operator/bracket

Answer 9

tokens = re.findall(r’\d+|[()+-*/]’, UserInput)

Question 10

ConvertToRPNWithBrackets ccode modification

Answer 10

for token in tokens:
if token.isdigit():
if 0 <= int(token) <= MaxNumber:
RPNQueue.append(token)
else:
pass

    elif token == '(':
        Operators.append(token)**
    
    elif token == ')':
        **# On encountering right bracket:

        while Operators and Operators[-1] != '(':
            RPNQueue.append(Operators.pop())

        if Operators and Operators[-1] == '(':
            Operators.pop()
    
    else:
       
   
        while (Operators and Operators[-1] != '(' and
               Precedence.get(Operators[-1], 0) >= Precedence[token]):
            RPNQueue.append(Operators.pop())

        Operators.append(token)


while Operators:
    RPNQueue.append(Operators.pop())

return RPNQueue

Question 11

brackets question : checkvalidoperator function

Answer 11

CHANGE

def CheckValidOperator(Item):
# Returns True if Item is one of the valid operators or brackets
return re.search(r”[+-*\/()]”, Item) is not None
#END CHANGE

Question 12

brackets question: updated checkifuserinputvalid function

Answer 12

change
def CheckIfUserInputValid(UserInput):
return re.fullmatch(r”[0-9+-*/()]+”, UserInput) is not None
## end change

Question 13

hint q using brute force (and using more than 2 numbers)

Answer 13

START CHANGE

def display_hint(Targets,NumbersAllowed):
Operators = list(‘+/-*’)
NumberOfHints = 5
Loop = 1000
while Loop > 0 and NumberOfHints > 0:
Loop -= 1
TempNumbersAllowed = NumbersAllowed.copy()
random.shuffle(TempNumbersAllowed)

    Guess = str(TempNumbersAllowed[0])
    for i in range(1, random.randint(1,4)+ 1):
        Guess += Operators[random.randint(0,3)]
        Guess += str(TempNumbersAllowed[i])
    EvaluatedAnswer = EvaluateRPN(ConvertToRPN(Guess))
    if EvaluatedAnswer != -1 and EvaluatedAnswer in Targets:
        print('hint:' + Guess)
        NumberOfHints -= 1
if Loop <= 0 and NumberOfHints == 5:
    print('i couldnt find a hint')

END CHANGE

Question 14

allow user to save

Answer 14

def SaveGameToFile(Targets, NumbersAllowed, Score):
try:
with open(“savegame.txt”,”w”) as f:
f.write(“ “.join(map(str, Targets)))
f.write(“\n”)
f.write(“ “.join(map(str, NumbersAllowed)))
f.write(“\n”)
f.write(str(Score))
f.write(“\n”)
print(“____Game saved____”)
print()
except:
print(“Failed to save the game”)

	def LoadGameFromFile():
try:
    with open("savegame.txt","r") as f:
        Targets = list(map(int, f.readline().split()))
        NumbersAllowed = list(map(int, f.readline().split()))
        Score = int(f.readline())
        print("\_\_\_\_Game loaded\_\_\_\_")
        print()
except:
    print("Failed to load the game")
    print()
    return [],[],-1
return Targets, NumbersAllowed, Score