Question

我创建了一个保存[24]个数据的数组，并在每个索引中分配了一些信息。我的问题是，当我想使用键盘上的Scanner调用索引时，假设我从用户那里调用了index [12]，下一次我要它说时，您已经选择了该号码，请选择其他号码，等等。基本上，我不应该两次调用相同的索引，最好使用什么。

非常需要您的帮助。

Answer 1

使用java.util.Set存储选定的索引，例如java.util.HashSet。

它应该像这样：

Set<Integer> selected = new HashSet<>();

int userInput = ...; // get input from user

while (selected.contains(userInput)) {
    // print u already selected that number, choose a different number so on so forth
    userInput = ...; // get input from user
}


selected.add(userInput);

// do something with the index

Answer 2

必须保存选定数字的索引，然后将所有新数字与列表元素进行比较。

Scanner s = new Scanner (System.in);
    int choice = s.nextInt();
    List<Integer> choiced = new ArrayList<Integer>();


     while (true) {//or your condition
         label:
        for (Integer i : choiced) {
            if (choice == i) {
                System.out.println("Index already selected, please select a different one");
                break label;
            }
        }
        choiced.add(choice);

        choice = s.nextInt();
    }

Answer 3

我尝试了两种方法，但仍然可以解决，这是我的代码，您将如何应用你们在此处编写的代码。

导入java.util.Scanner;

公共类主要{

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int number = 0;

    String [] differentChocolate = new String[24];
    differentChocolate[0]  = "You receive:  A star that weighs 7 grams";
    differentChocolate[1]  = "You receive:  Praline Bag Assorted 800g";
    differentChocolate[2]  = "You receive:  Kinder Surprise Santa 75g";
    differentChocolate[3]  = "You receive:  Woolworths Christmas Chocolate Net Bag 72g";
    differentChocolate[4]  = "You receive:  Quality Street Tub 726g";
    differentChocolate[5]  = "You receive:  Cadbury Favourites Snowman Bowl 700g";
    differentChocolate[6]  = "You receive:  Lindt Santa Pouch Bag 80g";
    differentChocolate[7]  = "You receive:  Praline Bag Assorted 800g";




    while (true){
        System.out.println("Choose a chocolate (0-23): ");
                number = in.nextInt();
                System.out.println(differentChocolate[number]);
            }
        }
    }

如何阻止用户再次选择相同的号码？

3 个答案: