带负数的Mod在Java和C中给出否定结果 [英] Mod with negative numbers gives a negative result in Java and C

问题描述

假设我有（ - 5）mod 8 。

我用两种语言Java和C，当我期待 3 时，他们给了我 -5 的结果。

I tried it in both languages Java and C, and they gave me a -5 result when I was expecting 3.

为什么会这样？模数可以为负数吗？我应该改变什么来获得正确的结果？

Why is this happening? Can a modulus be negative? And what should I change to get the correct result?

Java代码

public class Example {
    public static void main(String[] args) {
        int x;
        x = -5%8;
        System.out.println(x);
    }
}

C代码

int main(){
    int x;
    x = -5%8;
    printf("%d", x);
}

输出

推荐答案

％运算符被视为余数运算符，因此结果的符号与被除数的符号相同。

The % operator is treated as a remainder operator, so the sign of the result is the same as that of the dividend.

如果你想要模数函数，你可以这样做：

If you want a modulo function, you can do something like this:

int mod(int a, int b)
{
    int ret = a % b;
    if (ret < 0)
        ret += b;
    return ret;
}

这篇关于带负数的Mod在Java和C中给出否定结果的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！