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public class RandomNumber {
public static void main(String[] args) {
List<Integer> list=new ArrayList<Integer>();
Random roand= new Random();
int i=0;
while(i<5)
{
int num= roand.nextInt(10);
if(!list.contains(num))
{
list.add(num);
i++;
}
}
for(int j=0;j<list.size();j++)
{
System.out.println(list.get(j));
}
}
}
public List getRandomNumber(){
List all=new ArrayList();
for(int i=0;i<10;i++)all.add(i);//先放10个数到一个集合中
List num=new ArrayList();
for(int i=0;i<5;i++){ //获取5次
int index=(int)(Math.random()*(10-i));//每次产生一个随机索引
num.add(all.get(index));//获取索引处元素放置到num集合中
all.remove(index);//删除刚才已经获取的元素
//注意每删除一个all集合中少一个元素,索引范围会缩小
}
return num;
}
public List getRandomNumber(){
List num=new ArrayList();
Random r=new Random();
do{
int n=r.nextInt(10);
if(!num.contains(n))num.add(n);
}while(num.size()<5);
return num;
}
Random random = new Random();
Set<Integer> s = new HashSet<Integer>();
while(true){
int temp = random.nextInt(9);
s.add(temp);
if(s.size()==5) break;
}
for (Integer integer : s) {
System.out.println(integer);
}
import java.util.Random;
import java.util.Vector;
public class GetNum {
private Vector<Integer> nums = null;
private Random random = null;
public GetNum() {
nums = new Vector<Integer>(10);
for (int i = 0; i < 10; i++) {
nums.add(i);
}
random = new Random();
}
public Vector<Integer> getNum() {
Vector<Integer> temp = new Vector<Integer>(5);
for (int i = 0; i < 5; i++) {
Integer integer = nums.get(random.nextInt(nums.size()));
temp.add(integer);
nums.remove(integer);
}
return temp;
}
public static void main(String... args) {
GetNum num = new GetNum();
System.out.println(num.getNum());
}
}