这个部门有什么问题?

代码如下:

class testsum
{ 
    public static void main(String arg[]) 
    {
        double sum=0; 
        double fraction;
        fraction=-1/9;
        System.out.println("fraction: "+fraction); 
        fraction=-1; 
        fraction=fraction/9; 
        System.out.println("fraction: "+fraction); 
    } 
} 

输出是 0 然后是 -0.11111111

为什么第一个输出是 0 而不是 -0.11111111111?

why was the first output 0 and not -0.11111111111?

推荐答案

它在第一个示例中进行整数除法，因为这是数字文字的默认类型.尝试将其更改为 -1.0/9(或 1d/9d - d 后缀表示 double)，您应该会得到相同的答案.

It's doing integer division in the first example as this is the default type for a numeric literal. Try changing it to -1.0/9 (or 1d/9d - the d suffix indicates a double) and you should get the same answer.