Python和C++ 负数取余%计算

Python

for i in range(1,11):
    print("-10 %% %d = %d" %(i, -10%i))

计算结果：

-10 % 1 = 0
-10 % 2 = 0
-10 % 3 = 2
-10 % 4 = 2
-10 % 5 = 0
-10 % 6 = 2
-10 % 7 = 4
-10 % 8 = 6
-10 % 9 = 8
-10 % 10 = 0

可见Python中，以-10 % 9 = 8为例， -10 = 9 * (-2) + 8 来取余数8

C++

for (int i=1;i<=10;i++) {
        printf("-10 %% %d = %d\n",i,(-10)%i);
    }

计算结果：

-10 % 1 = 0
-10 % 2 = 0
-10 % 3 = -1
-10 % 4 = -2
-10 % 5 = 0
-10 % 6 = -4
-10 % 7 = -3
-10 % 8 = -2
-10 % 9 = -1
-10 % 10 = 0

可见C++中，以-10 % 9 = -1为例，-10 = 9 * （-1）+ （-1）来取余数-1

总结

在Python中，负数对正数取余，要保证余数是正数，所以会比C++中多算一个除数