java - 自增长数组java

Question

题目是实现get(int index)、set(intindex)这三个方法，以及SelfGrowingArray()中的构造函数为了产生主要方法中显示的句子。编译时，我得到一个 ArrayIndexOutofBoundsException，具体来说，这个错误:

[null, null, null, null, null, null, null, null, null, null, null, null, null, null, You don't know you're beautiful]
[null, null, null, null, null, null, null, null, null, null, null, null, null, null, You don't know you're beautiful, null, null, null, null, null, null, What doesn't kill you makes you stronger.]
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -14

这是我的代码，请帮忙:

public class SelfGrowingArray {

private Object[] data;

public SelfGrowingArray()
{
    data = new Object[0];
}

public void set(int index, Object value)
{
    if (index >= data.length) {
        Object[] newArray = new Object[index + 1];
        for (int i = 0; i < data.length; i++) {
        newArray[i] = data[i];
        }
        data = newArray;
        }
        data[index] = value;    
}

public Object get(int index)
{
    if (index >= data.length)
    return null;
    return data[index];
}

public String toString()
{
    if (data == null)
    {
        return "null";
    }

    int iMax = data.length - 1;
    if (iMax == -1)
    {
        return "[]";
    }

    StringBuilder b = new StringBuilder();
    b.append('[');
    for (int i = 0; ; i++)
    {
        b.append(data[i]);
        if (i == iMax)
        {
            return b.append(']').toString();
        }
        b.append(", ");
    }
}

public static void main(String[] args) {
    SelfGrowingArray myList = new SelfGrowingArray();
    myList.set(14, "You don't know you're beautiful");
    System.out.println(myList);

    myList.set(21, "What doesn't kill you makes you stronger.");
    System.out.println(myList);

    System.out.println("myList.get(-14) " + myList.get(-14));
    System.out.println("myList.get(14) " + myList.get(14));
    System.out.println("myList.get(15) " + myList.get(15));
    System.out.println("myList.get(31) " + myList.get(31));
    System.out.println("myList.get(32) " + myList.get(32));

}
}

Answer 1

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -14

问题出在这里:

myList.get(-14)

您不能访问小于 0 的索引。修改您的 get 方法以支持负索引:

public Object get(int index) {
    if (index >= data.length || index < 0) {
        return null;
    }
    return data[index];
}