英文:
How do I add to the first empty index in a generic type array?
问题
我正在从头开始使用通用类型（generic types）创建一个ArrayList类，其中我需要包含一个将元素添加到第一个空索引的方法。
我使用T[] list = (T[]) new Comparable[size];来初始化数组。
假设 size = 10; 并且索引0-3已填充了各种对象。我该如何找到索引4作为第一个空索引？通用类型的数组是用null还是其他方式初始化的？
谢谢。
英文:
I am making an ArrayList class from scratch using generic types, and one of the methods I need to include is one that adds an element to the first empty index in the arrayList.
I initialized the array with T[] list = (T[]) new Comparable[size];
Say size = 10; and indices 0-3 are filled with various Objects. How would I locate index 4 as the first empty index? Are generic arrays initialized with nulls or something else?
Thank you
答案1
得分: 0
在Java中，实际上有两种类型的数组：原始数组和对象数组。提示：泛型是对象。
原始数组的元素被初始化为0，或者对于boolean[]来说是false，而对象数组的元素则被初始化为null。
这些都是相同的默认值，也会赋予给给定类型的字段，例如，像这样的字段默认情况下将是null：
private Comparable<Foo> comparable;
英文:
There are really 2 types of arrays in Java: Primitive arrays and object arrays. Hint: Generics are objects.
The elements of primitive arrays are initialized to 0, or false for a boolean[], and the elements of object arrays are initialized to null.
Those are the exact same default values that are also assigned to fields of the given types, e.g. a field like this will be null by default:
private Comparable<Foo> comparable;
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