You have written some set functions. You now need some get functions.
int project::getName()
{
return name;
}
std::string project::getDuration( )
{
return duration;
}
Since the data is now private you cannot access it from outside the class. But you can use your get functions in your main function.
std::cout << " the name of the thesis is" << thesis.getName() << '\n';
std::cout << " the duration of the thesis is" << thesis.getDuration() << '\n';