数组索引与数组元素

Question

这是与以下问题相关的一种元问题：。

最初提出的问题（强调我的）：

I have a std::vector<int> data; and I want to find all the array indexes that are less than 9 and add them to a result vector.

然后我将其编辑为：

I have a std::vector<int> data, and I want to find all elements that are less than 9 and add them to a result vector.

然后另一个用户将其编辑为：

I have a std::vector<int> data and I want to find all array indices at which the elements are less than 9 and add them to a result vector.

我已将其标记为让版主恢复此内容，说明：

I reworded this question (whosebug.com/posts/38798841/revisions) with the main goal of replacing "array indexes" with "elements", since that is what's actually being asked - and referring to "indexes/indices" in this context causes some confusion. However, user Aconcagua has overturned this crucial part of my edit. It's my belief that his latest edit should be rolled back.

它被拒绝了，原因是：

Aconcagua's edit is correct; the user is collecting array indicies, not the array elements themselves

。

现在，我不太明白版主说的是什么 - "the user is collecting array indicies"。在我看来，索引是数组中元素的位置。比如C语言中：

char array[] = {'t', 'e', 's', 't'};
int index = 1;
char element = array[index];
printf('%c', element);

我根本不明白他会如何或为什么收集 "indices" 而不是 "elements"。谁能澄清一下，这样我才能真正理解？

Answer 1

在链接问题顶部的示例代码中：

for (int i = 0; i < data.size(); ++i)
    if (data[i] < 9)
        r.push_back(i);

注意 i 被添加到向量中，不是 data[i].

i 是感兴趣元素的索引，是正在存储的内容，而不是存储在 data[i] 的值，它是 data 向量中的元素。

数组索引与数组元素

Array Indices vs Array Elements

c

c++

arrays

indices