c++, unqualified-id before

Hello
I ve this two file:

Conversion.h, conversion.cpp

Code conversion.h:

using namespace std;
class Conversion
{
  public:
  Conversion();
};

Code Conversion.cpp

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

Conversion()
{
  cout << "test";
}

with g++ C.* I recive the following error:
Conversion.cpp:4: error: expected unqualified-id before ')' token

I really don't understand where is my mistake.
Any help will be very appreciate :)

Thanks 

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