STD

【標準（Standard）】

標準（Standard）

在C++中

std其實就是standard標準的意思~~

例如std::cin就是標準輸入

std::cout就是標準輸出的意思~:

一個標準庫名字空間

The std namespace

The ANSI/ISO C++ standard requires you to explicitly declare the namespace in the standard library. For example,when using iostream.h,you do not have to specify the namespace of cout in one of the following ways:

std::cout (explicitly)

using std::cout (using declaration)

using namespace std (using directive)

Visual C++ continues to support the use of older header filenames with the .h extension. Such usage does not require invocation of the std namespace described above.