It’s not a reserved word under ISO standards. Microsoft’s C++/CLI defines array in the cli namespace, and Visual Studio’s syntax highlighting will treat it as a reserved word. This usage would be considered a vendor extension and not a part of any international C or C++ standard.
ISO C99 Keywords:
auto enum restrict unsigned break extern return void case float short volatile char for signed while const goto sizeof _Bool continue if static _Complex default inline struct _Imaginary do int switch double long typedef else register union
ISO C++98 Keywords:
and double not this and_eq dynamic_cast not_eq throw asm else operator true auto enum or try bitand explicit or_eq typedef bitor export private typeid bool extern protected typename break false public union case float register unsigned catch for reinterpret_cast using char friend return virtual class goto short void compl if signed volatile const inline sizeof wchar_t const_cast int static while continue long static_cast xor default mutable struct xor_eq delete namespace switch do new template