Question

我很困惑为什么我的Object数组仍然相同。我试图从数组中计算索引。我如何计算指数？

public class TryArray {

    Students[] arr;

    public void add(Students std) {
        for (int i = 0; i < arr.length ; i++) {
            arr[i] = std;
         System.out.println(std); //it willbe more than one time displayed
            break;
        }
    }

    public TryArray(int lengthOfArray) { //Constructor for the length Array
        arr = new Students[lengthOfArray];
    }
}

这是我的主要课程test1.java

public class test1 {

    public static void main(String[] args) {
        TryArray val = new TryArray(4);
        Students a1 = new Students(1, "Bob", "Julius");
        Students a2 = new Students(2, "Joe", "Chris");
        Students a3 = new Students(3, "Christian", "Henderson");
        Students [] arr = {a1,a2,a3};       
        val.add(a1);
        val.add(a2);
        val.add(a3);
    }
}

预期输出：

1, Bob, Julius
2, Joe, Chris
3, Christian, Henderson

我错过了什么吗？

Answer 1

您当前的代码中存在很多误解。首先，您要使用要添加的元素设置数组的所有元素。其次，在add方法中，您可以在不考虑正确结果的情况下打印变量乘以数组长度。

TryArray类的代码可能会被重写为：

public class TryArray {

    //array to store the students (elements)
    private Students[] arr;
    //counter of how many students are stored by this instance
    private int size;

    public void add(Students std) {
        /*
        the code here makes no sense, see explanation above
        for (int i = 0; i < arr.length ; i++) {
            arr[i] = std;
         System.out.println(std); //it willbe more than one time displayed
            break;
        }
        */
        if (size < arr.length) {
            arr[size++] = std;
            //this is for testing purposes only, in real life code
            //you shall avoid code like this here
            System.out.println(std);
        }
    }

    public TryArray(int lengthOfArray) { //Constructor for the length Array
        arr = new Students[lengthOfArray];
    }
}

为什么我的对象数组的值在Java

1 个答案: