class SortedStack:
def __init__(self):
self._stack = ArrayStack()
def peek(self):
return self._stack.peek()
def pop(self):
return self._stack.pop()
def push(self, value):
temp = ArrayStack()
if self._stack.is_empty() or self._stack.peek() > value:
self._stack.push(value)
else:
hold = value
size = len(self._stack) + 1
while len(self._stack) != size:
if self.peek() < hold and self.peek() is not None:
temp.push(self.pop())
elif hold is not None:
self._stack.push(hold)
hold = None
else:
self._stack.push(temp.pop())
class MyQueue:
def __init__(self):
self._stack = ArrayStack()
self._inverted = False
self._size = 0
def peek(self):
# stack = self._stack
if self._stack.is_empty():
raise Empty('Stack is empty')
if not self._inverted:
self.invert_stack()
return self._stack.peek()
def push(self, value):
if self._inverted:
self.invert_stack()
self._stack.push(value)
def pop(self):
if self._stack.is_empty():
raise Empty('Empty stack')
if not self._inverted:
self.invert_stack()
return self._stack.pop()
def invert_stack(self):
temp = ArrayStack()
self._inverted = not self._inverted
while self._stack.peek() is not None:
temp.push(self._stack.pop())
self._stack = temp
class MathOps(ArrayStack):
def __init__(self):
self.current_value = ArrayStack()
self.current_value.push(0)
self.redo_stack = ArrayStack()
self.undo_stack = ArrayStack()
ArrayStack.__init__(self)
def evaluate_expression(self, right_operand, operator):
"""evaluate using inputed operater from current value w/ inputed right_operand and operator"""
left_operand = self.current_value.peek()
if operator == "+":
evaluated_value = left_operand + right_operand
if operator == "-":
evaluated_value = left_operand - right_operand
if operator == "/":
evaluated_value = left_operand / right_operand
if operator == "*":
evaluated_value = left_operand * right_operand
print("{} {} {} = {}\n".format(left_operand, operator, right_operand, evaluated_value))
self.current_value.push(evaluated_value)
def check_if_valid_operator(self, operater):
valid_operators = ['+', '*', '/', '-']
if operater not in valid_operators:
raise TypeError("This message won't show up, will go straight to except block")
else:
return operater
def parse_input(self, _input):
valid_strings = ['u', 'r', 'q']
if _input not in valid_strings:
try:
_input = int(_input)
operator = input("Enter an operation: ")
operator = self.check_if_valid_operator(operator)
self.evaluate_expression(_input, operator)
except:
print("Invalid Input. Try Again\n")
pass
if _input == 'u':
if self.current_value._size >= 2:
self.redo_stack.push(self.current_value.pop())
print("\n")
else:
print("No more actions to undo!\n")
if _input == 'r':
if self.redo_stack._size > 0:
self.current_value.push(self.redo_stack.pop())
print("\n")
else:
print("No more actions to undo!\n")
if _input == 'q':
print("Stopping Program\n")
return True
def run_script(self):
stop = False
while stop is not True:
print("Current value is {}".format(self.current_value.peek()))
input_string = input("Enter a number, 'u' to undo, 'r' to redo, 'q' to quit: ")
return_string = self.parse_input(input_string)
if return_string:
stop = True
