undefined reference to Class::Function() C++ [duplicate]

After searching for a solution to this for about a half an hour I have made no progress. The errors are as follows:

s\My Workspace\Project\main.cpp - Line 7 - undefined reference to 'Sally::Sally()'

s\My Workspace\Project\main.cpp - Line 9 - undefined reference to 'Sally::printCrap()'

main.cpp

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

int main()
{
    Sally sallyObject;
    sallyObject.printCrap();
}

Sally.h

#ifndef SALLY_H
#define SALLY_H


class Sally
{
    public:
        Sally();
        void printCrap();
};

#endif // SALLY_H

Sally.cpp

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

Sally::Sally(){
}

void Sally::printCrap(){
    cout << "Did someone say steak?" << endl;
}

Thank you in advance!