java - java中浮点值乘以-1

Question

为什么当 0.0 乘以 -1 时我得到 -0.0？？？我采用 0.0 作为 float

sign=-1;
float output=0.0;
JOptionPane.showmessagedialog(null,0.0*sign);

输出显示为 -0.0 而不是 0

Answer 1

这是来自http://www.javawebtips.com/154041/的答案

 "-0.0" Is produced when a floating-point operation results in a negative floating-point number so close to 0 that cannot be represented normally.

  -2.0 / Float.POSITIVE_INFINITY -> -0.0 

"-0.0" Is numerically identical to "0.0". However, some operations involving "-0.0" are different than the same operation with "0.0".

  (-0.0) == 0.0 -> true 
  2.0 / (0.0) - Infinity 
  2.0 / (-0.0) ->-Infinity