我尝试创建一个简单的彩票计划。这是一个问题:它仍然打印相同的数字。例如,我输出了33 21 8 29 21 10
。每当生成随机数时,代码会检查是否已生成该数字,然后它会创建一个新的随机数,但之后不会再次检查。我找不到办法做到这一点。
public static void main(String[] args)
{
int[] lottery = new int[6];
int randomNum;
for (int i = 0; i < 6; i++)
{
randomNum = (int) (Math.random() * 50); //Random number created here.
for (int x = 0; x < i; x++)
{
if (lottery[i] == randomNum) // Here, code checks if same random number generated before.
{
randomNum = (int) (Math.random() * 50);//If random number is same, another number generated.
}
}
lottery[i] = randomNum;
}
for (int i = 0; i < lottery.length; i++)
System.out.print(lottery[i] + " ");
}
答案 0 :(得分:7)
您正在检查时更改随机数。您需要选择一个随机数并检查它是否存在。
BTW较短的方法是使用随机播放。
// give me all the number 1 to 50
List<Integer> list = IntStream.range(1, 51).boxed().collect(Collectors.toList());
// shuffle them.
Collections.shuffle(list);
// give me the first 6
System.out.println(list.subList(0, 6));
答案 1 :(得分:7)
您的代码有两个问题:
lottery[i]
和randomNum
是否相同,应该是lottery[x]
lottery
中的第一个数字进行核对。以下是更正后的版本:
public static void main(String[] args) {
int[] lottery = new int[6];
int randomNum;
for (int i = 0; i < 6; i++) {
randomNum = (int) (Math.random() * 50); // Random number created here.
for (int x = 0; x < i; x++) {
if (lottery[x] == randomNum) // Here, code checks if same random number generated before.
{
randomNum = (int) (Math.random() * 50);// If random number is same, another number generated.
x = -1; // restart the loop
}
}
lottery[i] = randomNum;
}
for (int i = 0; i < lottery.length; i++)
System.out.print(lottery[i] + " ");
}
答案 2 :(得分:1)
一个简单的解决方案,介于第一个(非Java程序员可能非常抽象)和第二个(不确保数字列表的唯一性)之间。
Collection<Integer> liste = new ArrayList<Integer>();
for (int i = 0; i < 6; i++)
{
Boolean ap = false;
while (!ap)
{
Integer randomNumber = (int) (Math.random() * 50);
if (! liste.contains(randomNumber)){
liste.add(randomNumber);
ap = true;
}
}
}
for (Integer liste1 : liste) {
System.out.print(liste1+" ");
}
答案 3 :(得分:0)
试试这个,它创造了12 x(45个中的6个)
public static void main(String[] args) {
SecureRandom random = new SecureRandom();
for (int i = 0; i < 12; i++){
Integer[] tipp = new Integer[6];
int n = 0;
do {
int r = random.nextInt(45) + 1;
if (Arrays.asList(tipp).indexOf(r)<0){
tipp[n]= r;
n++;
}
} while (n<=5);
Arrays.sort(tipp);
System.out.println(Arrays.toString(tipp));
}
}
答案 4 :(得分:0)
public static void main(String[] arg) {
int[] lottery = new int[6];
int randomNum;
c1:
for (int i = 0; i < 6; i++) {
randomNum = (int) (Math.random() * 50); // Random number created here.
if(randomNum == 0) {
continue c1;
}
for (int x = 0; x < i; x++) {
if (lottery[x] == randomNum ) // Here, code checks if same random number generated before.
{
randomNum = (int) (Math.random() * 50);// If random number is same, another number generated.
x = -1; // restart the loop
}
}
lottery[i] = randomNum;
}
for (int i = 0; i < lottery.length; i++)
System.out.print(lottery[i] + " ");
}