import java.util.*;public class ShuffleTest
{ public static void main(String[] args)
{ List numbers = new ArrayList(40);
int maxcount=300;
for (int i = 0; i < maxcount; i++)
numbers.add(new Integer(i));
boolean check=true;
long start = System.currentTimeMillis();
Random generator = new Random();
String result="";
int cur=0;
long kao=0;
while(check){
cur=Math.abs((new Random(generator.nextLong())).nextInt())%maxcount;
result=String.valueOf((Integer)numbers.get(cur));
numbers.remove(cur);
maxcount=maxcount-1;
if(maxcount==0) check=false;
System.out.println(result);
//result.
kao++;
}
//System.out.println(result);
long end = System.currentTimeMillis();
System.out.print((end - start) + " milliseconds ");
System.out.print(kao+" counts ");
}
}
{ public static void main(String[] args)
{ List numbers = new ArrayList(40);
int maxcount=300;
for (int i = 0; i < maxcount; i++)
numbers.add(new Integer(i));
boolean check=true;
long start = System.currentTimeMillis();
Random generator = new Random();
String result="";
int cur=0;
long kao=0;
while(check){
cur=Math.abs((new Random(generator.nextLong())).nextInt())%maxcount;
result=String.valueOf((Integer)numbers.get(cur));
numbers.remove(cur);
maxcount=maxcount-1;
if(maxcount==0) check=false;
System.out.println(result);
//result.
kao++;
}
//System.out.println(result);
long end = System.currentTimeMillis();
System.out.print((end - start) + " milliseconds ");
System.out.print(kao+" counts ");
}
}
int[] a = new int[n];
for(int i = 0; i < a.length; i++)
{ label:
while(true){
int t = (int)(Math.random() * 300);
for(int j = 0;j < i; j++)
if(a[j] == t) continue label;
a[i] = t;
break;
}
}
data = new int[100];
给每个数组元素赋值
for (int i=0; i<data.length;i++){
swap(data[i] , data[random.nextint(100)] );
}如果结果不够随机可以多做几次for循环。一定要给分哦!
//:WhileTest.java
//Demonstrates the while looppublic class WhileTest{
public static void main(String[] args){
double r=0;
while(r<0.99d){
r=Math.random();
System.out.println(r);
}
}
}///:~
每运行一次程序,都会获得不同的数字!