int[] s={2,4,5,9,19};
java.util.Random rand = new java.util.Random(System.currentTimeMillis());
int the_number_you_want = s[Math.abs(rand.nextInt()) % s.length];
java.util.Random rand = new java.util.Random(System.currentTimeMillis());
int the_number_you_want = s[Math.abs(rand.nextInt()) % s.length];
int[] s={2,4,5,9,19};
int the_number_you_want =s[(int)(Math.random()*s.length)]
那么(int)(Math.random()*s.length=0
the_number_you_want =s[0]=2Math.random()=1那么(int)(Math.random()*s.length=5
the_number_you_want =s[5]=19请问,这叫随机吗?
random r=new random();
int b=a[r.nextInt(sa.length];这样OK了吗?