"Not declared in scope" C++ issue - c++

Question

I'm writing a simple class in C++ for a class (school, not code). I have a little C++ experience, but it's been a while so I'm relearning whatever I forgot and learning a lot of new syntax (I have much more experience in Java). Here is the code:
#include <iostream>
#include <string>
using namespace std;
class Project112
{
private:
string romanNumeral;
int decimalForm;
public:
Project112()
{
romanNumeral = "";
decimalForm = 0;
}
int getDecimal()
{
return decimalForm;
}
};
and here is the driver:
include cstdlib
include <iostream>
using namespace std;
int main()
{
Project112 x;
int value2 = x.getDecimal();
return 0;
}
This is part of a larger program, but I've simplified it down to this because this is the where the problem lies. Every time I try to run the program, I get the following errors:
main.cpp:10: error: 'Project112' was not declared in this scope
main.cpp:10: error: expected `;' before 'x'
main.cpp:14: error: 'x' was not declared in this scope
Can someone please explain the problem? Thanks in advance.

Answer 1

#include "Project112.h"
Add that above main. You forgot to include the header file. And:
using namespace std;
Don't do that in a header file. That imports the everything from the std namespace into the global namespace of any file which includes your header. Just fully qualify the type in a header, i.e., std::string, and I would avoid that in implementation files as well in a large project (though something like using std::string is ok IMO in an implementation file).