Differences between a modulo operation and a remainder operation

In general, MOD and REM operations are confused, because mostProgramming Language'%'Symbol indicates the modulo operation or the remainder operation. Here, we would like to remind everyone to pay attention to the current environment'%'Specific meaning of the operator, because when a negative number exists, the two results are different.

For integer a and B, the modulo operation or remainder operation methods are as follows:

1. Calculate the integer quotient: c = A/B;

2. calculation mode or remainder: r = a-c * B.

The modulo operation and the remainder operation are different in the first step:ModuloWhen the remainder operation obtains the value of C, it rounds to 0 (the fix () function );WhileRemainderWhen the modulo operation calculates the value of C, it rounds the floor () function to an infinitely small direction ).

Therefore, when the symbols A and B are the same, the result is the same because the modulo operation and the result of the remainder operation are the same. But when the symbols are inconsistent, the results are different.

Specifically, the result of the modulo operation is the same as that of B, and the result of the remainder operation is the same as that of..

In C, the % symbol represents the remainder operation. In a Python script, % Represents the modulo. (In the modulo operation, B is not allowed to be a negative number, but in Python 2.5.1, it can be followed by a negative number after %, because in Python, the division result is rounded to 0, therefore, the calculation result is a modulo !)

The following table lists some typical modulo or remainder values.

A	B	C language: A % B (remainder)	Python shell: A % B (Modulo)
-3	-5	-3	-3
-3	4	-3	1
-3	2	-1	1
-1	6	-1	5
-4	-3	-1	-1
2	4	2	2
5	3	2	2
4	-7	4	-3
4	-3	1	-2
-6	-5	-1	-1