Question

Non-positive number division is quite different in c++ and python programming langugages:

//c++:
11 / 3 = 3
11 % 3 = 2
(-11) / 3 = -3
(-11) % 3 = -2
11 / (-3) = -3
11 % (-3) = 2
(-11) / (-3) = 3
(-11) % (-3) = -2

So, as you can see, c++ is minimizing quotient.
However, python behaves like that:

#python
11 / 3 = 3
11 % 3 = 2
(-11) / 3 = -4
(-11) % 3 = 1
11 / (-3) = -4
11 % (-3) = -1
(-11) / (-3) = 3
(-11) % (-3) = -2

I can’t code my own division function behaving like c++, because I’ll use it for checking c++ calculator programs, and python does not support infix operators. Can I make python behaving like c++ while dividing integers in a simple way? For example, setting some flag or something like that?

Answer 1

As Thomas K said, use math.fmod for modulo, or if you really want you can define it yourself:

def cmod(x, y):
    return abs(x) % abs(y) * (1 if x > 0 else -1)

And this function should emulate C-style division:

def cdiv(x, y):
    return abs(x) / abs(y) * cmp(x, 0) * cmp(y, 0)

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You said that you must use the / and % operators. This is not possible, since you can’t override the operator for built-ins. You can however define your own integer type and operator overload the __div__ and __mod__ operators.