很多用例，所以让我们来看看它们是不可或缺的一些情况：

There are many use-cases, so let's look at a couple of situations where they are indispensable:

• 固定大小的数组或 matrix 类，请参阅示例C ++ 11 std :: array 或 boost :: array

• Fixed sized array or matrix classes, see for example C++11 std::array or boost::array.

std :: begin ，或任何需要固定大小C样式数组大小的代码，例如：

A possible implementation of std::begin for arrays, or any code that needs the size of a fixed size C style array, for example:

返回数组的大小：

template <typename T, unsigned int N>
unsigned int size(T const (&)[N])
{
  return N;
}

它们在模板元编程中也非常有用。

They are also extremely useful in template metaprogramming.