问题
Possible Duplicate:
Generating random number in a range with Java
double x = //Random number between -0.5 and 0.5
Possible Outputs:
-0.23
0.01
0.26
-0.4
How do I generate a double between the range of (example) -0.5 and 0.5?
回答1:
This should do it
Math.random() - 0.5
Math.random will generate betweeen 0 and 1. If you want between -0.5 and +0.5 then you can just -0.5 from this result. See the API docs
One thing that this will not do is ever give you 0.5 as Math.random() does never return 1. This post will give you more details and a possible solution.
回答2:
return min + Math.random() * (max - min);
来源：https://stackoverflow.com/questions/12395127/generate-random-double-between-x-and-x