問題描述
我對迭代器上的 next() 方法有疑問.如果我將這行代碼作為我的代碼的一部分(使用 arrayOfStrings size = 4):
I have a doubt with the next() method on iterators. If I have as a part of my code this lines (with arrayOfStrings size = 4):
Iterator<String> it = arrayOfStrings.iterator(); //arrayOfString is ArrayList<String>
while(it.hasNext()) {
String e = it.next();
System.out.println(e);
}
在第一次迭代時，迭代器開始指向索引為 0 的元素?還是像索引-1"?
At the very first iteration, the iterator starts pointing to element with index 0? or like the "index -1" ?
我問是因為據我所知 next() 方法返回集合中的下一個元素.
I ask because as far as I know the next() method returns the next element in the collection.
所以，如果在第一次迭代中，當調用 next() 時迭代器從索引 0 開始，它會返回索引 1 處的元素，我將無法對索引為 0 的元素?
So, if at the very first iteration the iterator starts at index 0 when next() is invoked, it returns the element at index 1 and I won′t be able to do nothing with the element at index 0?
推薦答案
將 next 視為一個兩步過程.首先它獲取迭代器中的下一項，然后遞增指針以指向下一項.因此，當您創建一個新的迭代器時，它會被初始化為返回列表中的第一項(索引 0).
Think of next as a two-step process. First it gets the next item in the iterator, then it increments the pointer to point to the next item. So, when you create a new iterator, it is initialized to return the first item (index 0) in your list.
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