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

write this code, it works perfectly..

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

using namespace std;

int main()
{
 cout<<"Hello World!";
  return 0;
}

Answer 2

In Visual studio use all your header filer below "stdafx.h".

Answer 3

The include "stdafx.h" is ok

But you can't use cout unless you have included using namespace std

If you have not included namespace std you have to write std::cout instead of simple cout

Answer 4

The code below compiles and runs properly for me using gcc. Try copy/pasting this and see if it works.

#include <iostream>
using namespace std;

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

int main () {
    int a = 1;
    bob(a);
    return 0;
}

Answer 5

In VS2017, stdafx.h seems to be replaced by pch.h see this article,

so use:

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

using namespace std;

int main() {
    cout << "Enter 2 numbers:" << endl;

Answer 6

In Visual Studio you must #include "stdafx.h" and be the first include of the cpp file. For instance:

These will not work.

#include <iostream>
using namespace std;
int main () {
    cout << "hey" << endl;
    return 0;
}




#include <iostream>
#include "stdafx.h"
using namespace std;
int main () {
    cout << "hey" << endl;
    return 0;
}

This will do.

#include "stdafx.h"
#include <iostream>
using namespace std;
int main () {
    cout << "hey" << endl;
    return 0;
}

Here is a great answer on what the stdafx.h header does.