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).