Java 为添加到ArrayList的对象生成编号

我已经创建了一个ArrayList，我想在其中根据用户输入为事件添加参与者。每一个加入的参与者将自动获得一个起始号码，第一个参与者将获得号码100。对于每增加一名参与者，开始人数将增加一名（101、102、103等），有何建议

这是到目前为止我的代码：

public void addParticipant() {

    int startNumber = 100;

    System.out.println("First name: ");
    String name = readString();
    System.out.println("Last name: ");
    String lastName = readString();
    System.out.println("Team: ");
    String team = readString();

    allParticipants.add(new Participant(name, lastName, team, startNumber));

    System.out.println(name + " " + lastName + " from " + team + " with number " + startNumber + " added \n");

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将startNumber存储为实例变量，而不是函数中的局部变量。在添加新参与者后增加变量

private int startNumber = 100;

public void addParticipant(){
    // Assign the startNumber to the new participant.
    startNumber++;
}

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有两种简单的方法可以做到这一点

第一种方法：不要将参与者编号存储在局部变量中，而是将其存储在字段（实例变量）中，并在每次添加新参与者时将其递增一。我会是这样的：

public class SomeClass {

    private int startNumber = 100;

    // any other code in the class...

    public void addParticipant() {

        System.out.println("First name: ");
        String name = readString();
        System.out.println("Last name: ");
        String lastName = readString();
        System.out.println("Team: ");
        String team = readString();

        allParticipants.add(new Participant(name, lastName, startNumber));

        System.out.println(name + " " + lastName + " from " + team + " with number " + startNumber + " added \n");

        // Increment field startNumber
        startNumber = startNumber + 1;
    }
}

第二种方式：使用ArrayList的大小作为计数器。这就是我的意思：

public class SomeClass {

    // any other code in the class...

    public void addParticipant() {

        int startNumber = allParticipants.size() + 100;

        System.out.println("First name: ");
        String name = readString();
        System.out.println("Last name: ");
        String lastName = readString();
        System.out.println("Team: ");
        String team = readString();

        allParticipants.add(new Participant(name, lastName, startNumber));

        System.out.println(name + " " + lastName + " from " + team + " with number " + startNumber + " added \n");
    }
}

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快乐编码

只需使用

allParticipants

的大小，并将其添加到

startNumber

？有许多可能实现这一点的实现。