Question

1. We want to add a button to the tally counter in Section 9.2 that allows an operator to undo an accidental button click. Provide a method def undo(self) that simulates such a button. As an added precaution, make sure an undo doesn't cause the counter to be less than zero. 5 pts a) Your code with comments b) A screenshot of the execution Test Case: Reset 2 clicks Print Value 1 click Print Value 2 undos Print Value 2 undos Print Value

Answer 1

Answer:

See explaination

Explanation:

class Counter:

def getValue(self):

return self._value

def undo(self):

if self._value > 0:

self._value = self._value - 1;

def click(self):

self._value= self._value + 1

def reset(self):

self._value= 0

tally= Counter()

tally.reset()

tally.click()

tally.click()

result = tally.getValue()

print("Value:", result)

tally.click()

result = tally.getValue()

print("Value:", result)

tally.undo()

tally.undo()

result = tally.getValue()

print("Value:", result)

tally.undo()

tally.undo()

result = tally.getValue()

print("Value:", result)