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In Python, when a int bigger than 2**31, then it will turn to a long:
a = 2147483647
a + 1 = 2147483648
b = -2147483648
b - 1 = -2147483649
but I need the Python int overflow like the int in C:
a = 2147483647
a + 1 = -2147483648
b = -2147483648
b - 1 = 2147483647
Is it possible? thanks in advance!
367
Arbitrary precision of Integers: In python, integers have arbitrary precision and therefore we can represent an arbitrarily large range of integers they can be only limited by memory available. Hence the Integers in python never Overflows as such in c and c++.
In languages where integer overflow can occur, you can reduce its likelihood by using larger integer types, like Java's long or C's long long int. If you need to store something even bigger, there are libraries built to handle arbitrarily large numbers.
An integer overflow can cause the value to wrap and become negative, which violates the program's assumption and may lead to unexpected behavior (for example, 8-bit integer addition of 127 + 1 results in −128, a two's complement of 128).
You can combine both of your functions to make just one function, and using list comprehension, you can make that function run in one line. You cannot prevent overflow errors if you are working with very large numbers, instead, try catching them and then breaking: import math def fib(j): try: for i in [int(((1+math.
Try numpy:
>>> x = numpy.int32(2147483647)
>>> x
2147483647
>>> type(x)
<type 'numpy.int32'>
>>> x+1
__main__:1: RuntimeWarning: overflow encountered in long_scalars
-2147483648
>>> type(x+1)
<type 'numpy.int32'>
Just make sure to call int on these things before passing them to code that expects normal Python overflow behavior.
117
You can define your own class and override the __int__() special method, along with various other mathematical operator special methods, to emulate a numeric type. Then your class can maintain the invariant that the value is always in the proper range.
For example:
def class Int32:
def __init__(self):
self.value = 0
def __init__(self, value):
# Wrap value into [-2**31, 2**31-1]
self.value = (value + 2**31) % 2**32 - 2**31
def __int__(self):
return self.value
def __add__(self, other):
return Int32(self.value + other.value)
# ... etc. for other mathematical operators
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