Counting from zero is a very common practice in many computer languages, but why? Read on as we explore the phenomenon and why it is so widespread.

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

问题

超级用户读者DragonLord很好奇为什么大多数操作系统和编程语言都是从零开始计算的。他写道：

Computers traditionally tally numerical values starting from zero. For example, arrays in C-based programming languages start from index zero.

What historical reas*** exist for this, and what practical advantages does counting from zero have over counting from one?

为什么呢？尽管这种做法很普遍，但实施这种做法肯定有实际原因。

答案

超级用户贡献者Matteo提供了以下见解：

Counting arrays from 0 simplifies the computation of the memory address of each element.

If an array is stored at a given position in memory (it’s called the address) the position of each element can be computed as

If you c***ider the first element the first, the computation becomes

Not a huge difference but it adds an unnecessary subtraction for each access.

Edited to add:

• The usage of the array index as an offset is not a requirement but just an habit. The offset of the first element could be hidden by the system and taken into c***ideration when allocating and referencing element.
• Dijkstra published a paper “Why numbering should start at zero” (pdf) where he explains why starting with 0 is a better choice. Starting at zero allows a better representation of ranges.

如果你想更深入地探究答案，Dijkstra的论文是一本信息丰富的读物。

有什么要补充的解释吗？在评论中发出声音。想从其他精通技术的Stack Exchange用户那里了解更多答案吗？在这里查看完整的讨论主题。