代码中的C ++ STD错误

Question

I just started c++

here is the code for a basic main declaration and based on many tutorails I have found, also contains the code to print hello world to console

// TestApp.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"


int _tmain(int argc, _TCHAR* argv[])
{
    std::cout << "Hello World";
}

I am using VS 2012 Express, I dont know which compiler but the "cout" is underlined in red

errors are as follows:

error C2039 'cout': is nit a member of 'std' ln 9 col 1 error C2065 : undeclared identifier ln 9 col 1 IntelliSense: namespace "std" has no member "cout" ln 9 col 7

I do not understand why it is giving an error, could someone please enlighten me?

Answer 1

The error is telling you that std::cout hasn't yet been declared anywhere in this translation unit. You can't use something if it hasn't been declared. std::cout is declared in the C++ standard library <iostream> header:

#include <iostream>

If you receive a similar error in the future and you need to know which header to include, look up some documentation for the particular function/type you want to use. For example, if you look at cppreference.com , it states "Defined in header <iostream> ".

Answer 2

包括以下代码：

#include <iostream>

Answer 3

Try this:

#include "stdafx.h"
#include <iostream>

int _tmain(int argc, _TCHAR* argv[])
{
    std::cout << "Hello World";
}

should be fine now