# MENU-DRIVEN STACK CODE


############ CHECK IF STACK IS FULL #################

def IsFull():
    global StackTop
    if (StackTop + 1 == MaxSize):
        # THEN
        StackFull = True
    else:
        StackFull = False
    # ENDIF
    return StackFull

#END IsFull.

def IsFull2():
    global StackTop
    return(StackTop + 1 == MaxSize)
#END IsFull2.

#####################################################


############ CHECK IF STACK IS EMPTY #################

def IsEmpty():
    global StackTop
    if (StackTop == -1):
        # THEN
        StackEmpty = True
    else:
        StackEmpty = False
    # ENDIF
    return StackEmpty

#END IsEmpty.

def IsEmpty2():
    global StackTop
    return(StackTop == -1)
#END IsEmpty2.

#####################################################

############### PRINT STACK #################

def PrintStack():
    global StackTop
    LocalTop = StackTop
    print(" ")
    print("The Stack is: ") 
    print("===========")
    while (LocalTop != -1):
       print(Stack[LocalTop])
       LocalTop = LocalTop - 1
    print("===========")
#END PrintStack.


############### PUSH ONTO THE STACK #################

def Push(N):
    global StackTop
    if (IsFull() == True):
        # THEN
        print("The stack is full")
    else:
        StackTop = StackTop + 1
        Stack[StackTop] = N
    # ENDIF

#END IsFull.


#####################################################

################ POP OFF THE STACK ##################

def Pop():
    N = 0
    global StackTop
    if (IsEmpty() == True):
        # THEN
        print("The stack is Empty")
    else:
        N = Stack[StackTop]
        StackTop = StackTop - 1
    # ENDIF
    return N

#END IsFull.


#####################################################


################ TOP OFF THE STACK ##################

def Top():
    N = 0
    global StackTop
    if (IsEmpty() == True):
        # THEN
        print("The stack is Empty")
    else:
        N = Stack[StackTop]
    # ENDIF
    return N

#END IsFull.


#####################################################

#########################################
# MAIN PROGRAM
#########################################

Stack = [31,41,59,26,53,59,67]
MaxSize = 7
StackTop =  5
choice = ''

while (choice != '9'):
   print("Select Operation.")
   print("1. Check if the Stack is Empty")
   print("2. Check if the Stack is Full")
   print("3. Add to Stack")
   print("4. Pop from Stack")
   print("5. Top of Stack")
   print(" ")
   print("9. Exit")
   print(" ")
   choice = input("Enter choice: ")

   if choice == '1':
      AnswersEmpty = IsEmpty()
      print(AnswersEmpty)
      PrintStack()
   elif choice == '2':
      AnswersFull = IsFull()
      print(AnswersFull)
      PrintStack()
   elif choice == '3':
      PushVal = input("Enter value to add:")
      Push(PushVal)
      PrintStack()
   elif choice == '4':
      PopVal = Pop()
      print(PopVal)
      PrintStack()
   elif choice == '5':
      TopVal = Top()
      print(TopVal)
      PrintStack()
   elif choice == '9':
      print("Exiting")
   else:
      print("Invalid input")
   #ENDIF

#ENDWHILE
#########################################

# END.