是否与额外的“，”，“在大括号初始化的结束？ [英] Is there any relevance to an extra "," in the end of a brace initialization?

问题描述

以下两个声明之间有区别，除了明显的名称：

Is there a difference between the following two declarations, aside from the obvious - the names:

int main()
{
    char str1[17] = {'H','e','l','l','o'};
    char str2[17] = {'H','e','l','l','o',};
}

第二个额外的'，'是什么？是否意味着任何东西？

What's up with the extra ',' in the second one? Does it mean anything at all?

这两个似乎编译只是罚款，在这种情况下，他们似乎生成相同的字符串根据strcmp，这至少是我期望的，因为

Both seem to compile just fine and in this case they seem to produce identical strings according to strcmp, which at least is what i expected since the rest of the arrays is filled with zeros.

推荐答案

尾部逗号不是特定于大括号初始化，而是无处不在的编程语言（JSON数据格式是一个异常值）。

The trailing comma isn't specific to brace-initialisation and is ubiquitous among programming languages (JSON data format being an outlier).

除了容易的机器生成，从尾部逗号获得的一个（小）好处是更小的代码差异。如果您更改：

Except for easy machine generation, one (small) benefit you get from trailing commas is smaller code differences. If you change:

array<string, 20> a = {
    "one",
    "two",
    "three",
};

到

array<string, 20> a = {
    "one",
    "two",
    "three",
    "four",
};

您只能得到一行差异。如果省略可选的尾部逗号，则需要更改2行以添加或删除最后一个元素。在编辑和读取差异时，一致使用尾随逗号可以节省您的时间。

you only get 1 line of difference. If you omit the optional trailing comma, you need to change 2 lines to add or remove the last element. Consistent use of the trailing comma saves you seconds while editing and reading diffs.

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