Typo at msdn page “C++ Constant Expressions”?

问题

It says at msdn page for c++ constant expressions that:

Nonintegral constants must be converted (either explicitly or implicitly) to integral types to be legal in a constant expression. Therefore, the following code is legal:

const double Size = 11.0;
char chArray[(int)Size];

At least on VC++ 10.0 the second line produces: "error C2057: expected constant expression". So is it legal on some other compiler or is the msdn page simply wrong?

回答1:

According to 5.19/1 :

An integral constant-expression can involve only literals (2.13), enumerators, const variables or static data members of integral or enumeration types initialized with constant expressions (8.5), non-type template parameters of integral or enumeration types, and sizeof expressions. Floating literals (2.13.3) can appear only if they are cast to integral or enumeration types.

From my understanding the code is invalid, while the following is legal :

char chArray[(int)11.0];

回答2:

That's not legal according to Standard C++. See 5.19/2 for the rules in the spec.

来源：https://stackoverflow.com/questions/4518787/typo-at-msdn-page-c-constant-expressions