error C2065: 'cout' : undeclared identifier

Question

I am working on the \'driver\' part of my programing assignment and i keep getting this absurd error:

error C2065: \'cout\' : undeclared identifier

Answer 1

I came here because I had the same problem, but when I did #include "stdafx.h" it said it did not find that file.
What did the trick for me was: #include <algorithm>.
I use Microsoft Visual Studio 2008.
These are the things that you can use then, incl. 'count': Link

Answer 2

I have seen that if you use

#include <iostream.h>

then you will get the problem.

If you use

#include <iostream>  

(notice - without the .h)

then you will not get the problem you mentioned.

Answer 3

I've seen similar things happen when I was using the .c file extension with C++ code. Other than that, I'd have to agree with everyone about a buggy installation. Does it work if you try to compile the project with an earlier release of VS? Try VC++ Express 2008. Its free on msdn.

Answer 4

I had the same issue when starting a ms c++ 2010 project from scratch - I removed all of the header files generated by ms and but used:

#include "stdafx.h"
#include <iostream>
using namespace std;

int main() {
   cout << "hey" << endl;
   return 0;
}

I had to include stdafx.h as it caused an error not having it in.

Answer 5

I ran across this error after just having installed vs 2010 and just trying to get a nearly identical program to work.

I've done vanilla C coding on unix-style boxes before, decided I'd play with this a bit myself.

The first program I tried was:

#include "stdafx.h"


int _tmain(int argc, _TCHAR* argv[])
{
    cout << "Hello World!";
    return 0;
}

The big thing to notice here... if you've EVER done any C coding,

int _tmain(int argc, _TCHAR* argv[])

Looks weird. it should be:

int main( int argc, char ** argv )

In my case I just changed the program to:

#include <iostream>
using namespace std;

int main()
{
     cout << "Hello world from  VS 2010!\n";
     return 0;
}

And it worked fine.

Note: Use CTRL + F5 so that the console window sticks around so you can see the results.

Answer 6

is normally stored in the C:\Program Files\Microsoft Visual Studio 8\VC\include folder. First check if it is still there. Then choose Tools + Options, Projects and Solutions, VC++ Directories, choose "Include files" in the "Show Directories for" combobox and double-check that $(VCInstallDir)include is on top of the list.