How to emulate 4-bit integer in Python 3?

Question

I\'d like to emulate overflow behavior of unsigned 4-bit integers, like this:

>>> x, y = Int4(10), Int4(9)
>>> x + y
Int4(3)
>>> x * y         


        

Answer 1

Overriding the __add__ method is a good idea, because you can make your calculations look clearly. Int4(4) + Int4(7) looks better than Int4(4).addTo(Int4(7)) (or something like this). Here is the code that could help you:

class Int4:
  def __init__(self, num): # initialising
    self.num = self.cap(num)

  def __str__(self):
    return str(self.num)

  def __repr__(self):
    return "Int4(" + self.__str__() + ")"

  def __add__(self, other): # addition
    return Int4(self.cap(self.num + other.num))

  def __sub__(self, other): # subtraction
    return Int4(self.cap(self.num - other.num))

  @staticmethod
  def cap(num): # a method that handles an overflow
    while num < 0:
      num += 16
    while num >= 16:
      num -= 16
    return num

And testing it:

>>> x,y,z = Int4(5), Int4(8), Int4(12)
>>> x
Int4(5)
>>> y
Int4(8)
>>> z
Int4(12)
>>> print x+y
13
>>> print z+y
4
>>> print x-z
9