R.2: In interfaces, use raw pointers to denote individual objects (only)
R.2: 接口中只在表示單獨對象時使用原始指針
Reason(原因）
Arrays are best represented by a container type (e.g., vector (owning)) or a span (non-owning). Such containers and views hold sufficient information to do range checking.
數組最好用容器類型（例如，vector(具有所有權)）或者span(不包含所有權)表示。容器或span包含可以用於範圍檢查的信息。
Example, bad(反面示例)
<code>void f(int* p, int n) // n is the number of elements in p[]
{
// ...
p[2] = 7; // bad: subscript raw pointer
// ...
}/<code>
The compiler does not read comments, and without reading other code you do not know whether p really points to n elements. Use a span instead.
編譯器不會讀註釋行，如果不看其他代碼你無法知道p實際上指向n個元素。使用span吧。
Example(示例)
<code>void g(int* p, int fmt) // print *p using format #fmt
{
// ... uses *p and p[0] only ...
}/<code>
Exception(例外)
C-style strings are passed as single pointers to a zero-terminated sequence of characters. Use zstring rather than char* to indicate that you rely on that convention.
C風格字符串作為指向以0結尾的字符序列的指針傳遞。使用zstring而不是char*以表明你遵守這個習慣。
Note(注意)
Many current uses of pointers to a single element could be references. However, where nullptr is a possible value, a reference may not be a reasonable alternative.
很多目前指向單獨要素的指針可以使用引用。然而，當nullptr也是有效值時引用就不是一個合理的選擇。
Enforcement(實施建議)
- Flag pointer arithmetic (including ++) on a pointer that is not part of a container, view, or iterator. This rule would generate a huge number of false positives if applied to an older code base.
- 如果一個指針不是來自容器，view或者迭代器並存在指針運算（包括++），進行提示。這條準則如果運用於舊代碼會產生大量的假陽性結果（結果有問題但實際上沒有問題，譯者注）。
- Flag array names passed as simple pointers
- 提示用原始指針傳遞數組的情況。
原文鏈接：
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#r2-in-interfaces-use-raw-pointers-to-denote-individual-objects-only
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