我需要添加什么，让我的Python 3程序检查输入是升序还是降序？

Question

I need to make my program to check whether the input is in ascending order on in descending order. It works already, however not correctly, I believe I need to add something more? I am very new to programming.

Here is my code :

b = 0
last = int(input()) 

finished= False
while not finished:
  new = int(input())
  if new == -1:
    finished = True
  elif last == -1:
    finished = True
  elif new > last :
    b = 1
  elif new <= last:
    b = 2
  last = new

if b == 1:
  print ('yes')
elif b == 2:
  print ('no') 

Answer 1

You should consider the values of b :

b = 0
last = int(input()) 

while True:
    new = int(input())
    if (new == -1) or (last == -1):
        break
    elif new > last :
        if b == 2: # this has been descending until now
            b = 0 # neither ascending nor descending
            break
        b = 1
    elif new < last:
        if b == 1: # this has been ascending until now
            b = 0
            break
        b = 2
    else: # when two adjacent values are equal, this order is neither ascending, nor descending
        b = 0
        break
    last = new

if not b:
    print("Neither ascending, nor descending")
elif b == 1:
    print ('ascending')
elif b == 2:
    print ('descending')
else:
    print("This is odd, we shouldn't have got here...")

Answer 2

This will continue asking the user for inputs until it receives a -1 as input. If there's a single input that makes the list in descending order, it will print 'no' at the end of the loop (when the user inputs -1 ).

b = 0
last = int(input('Last: ')) 

while True:
  new = int(input('New: '))     
  if new == -1 or last == -1:
      break
  elif new <= last:
    b = 2
  last = new

if b == 2:
  print ('no')
else:
  print ('yes')