在C ++中，数组有一个常量大小。然而，在C99中，存在称为可变长度数组或VLA的东西。这是你在这里做的。

In C++, arrays have a constant size. In C99, however, there exist something called variable-length arrays, or VLA's. This is what you're making here.

g ++ （C ++编译器）是 gcc （C编译器）和 g ++ 允许你使用C99特性，而VS没有这样的事情。基本上它是一个非标准的C ++扩展。

g++ (the C++ compiler) is a sibling of gcc (the C compiler), and g++ is allowing you to use that C99 feature, while VS has no such thing. Essentially it's a non-standard C++ extension.

如果你使 i （因为是标准C ++）：

If you make i a compile-time constant, it would work (since that's standard C++):

const int i = 256; // obviously cannot change at runtime.

如果您需要C ++中的动态数组，请使用 std :: vector 。

If you need a dynamic array in C++, use std::vector.

注意，在C ++中，您需要为 main 指定返回类型。这总是 int 。

Note in C++ you need to specify a return type for main. This is and always shall be int.