#!/usr/bin/python
# -*- coding: utf-8 -*-
class ElementOperator:
def add(self, num1, num2):
# 32bits integer max/min
MAX = 0x7FFFFFFF
MASK = 0xFFFFFFFF
ans = num1
while num2 != 0:
ans = (num1 ^ num2) & MASK
num2 = ((num1 & num2) << 1) & MASK
num1 = ans
return ans if ans <= MAX else ~(ans ^ MASK)
def subtract(self, num1, num2):
mid = self.add(~num2, 1)
return self.add(num1, mid)
def is_negative(self, num1, num2):
return (num1 ^ num2) < 0
def abs(self, num):
if num >= 0:
return num
else:
return self.add(~num, 1)
def multiply(self, num1, num2):
abs1 = self.abs(num1)
abs2 = self.abs(num2)
ans = 0
while abs2 != 0:
if abs2 & 1:
ans = self.add(ans, abs1)
abs2 = abs2 >> 1
abs1 = abs1 << 1
if self.is_negative(num1, num2):
return self.add(~ans, 1)
return ans
def divide(self, num1, num2):
# exception
if num2 == 0:
raise Exception("Divisor is zero.", num2)
abs1 = self.abs(num1)
abs2 = self.abs(num2)
ans = 0
i = 31
while i >= 0:
if (abs1 >> i) >= abs2:
ans = self.add(ans, 1 << i)
abs1 = self.subtract(abs1, abs2 << i)
i = self.subtract(i, 1)
if self.is_negative(num1, num2):
return self.add(~ans, 1)
return ans
if __name__ == '__main__':
s = ElementOperator()
print(s.add(5, 2))
转载于:https://www.cnblogs.com/c-x-a/p/10966454.html
