C++ Inheritance "No Viable Conversion" Error - c++

Question

Can someone let me know what I am doing wrong? I am making the object in my main and trying to pass a string variable to its setter. I keep getting the same error "No viable conversion"
#define PatientType_hpp
#include "PersonType.hpp"
#include "DoctorType.hpp"
#include "dataType.hpp"
class PatientType : public PersonType
{
private:
DoctorType drName;
public:
DoctorType getDrName() const;
void setDrName(DoctorType);
};
#endif /* PatientType_hpp */
//setters and getters
DoctorType PatientType::getDrName() const {
return drName;
}
void PatientType::setDrName(DoctorType drName) {
this->drName = drName;
}
#ifndef DoctorType_hpp
#define DoctorType_hpp
#include "PersonType.hpp"
#include <stdio.h>
class DoctorType: public PersonType
{
private:
string drSpecialty;
public:
string getDrSpecialty()const;
void setDRSpecialty(string);
};
#endif /* DoctorType_hpp */
#include "DoctorType.hpp"
#include <iostream>
string DoctorType::getDrSpecialty()const
{
return drSpecialty;
}
void DoctorType::setDRSpecialty(string drSpecialty)
{
this->drSpecialty=drSpecialty;
}
int main(int argc, const char *argv[]) {
PatientType example;
string drName = "Mr.Scott";
example.setDrName(drName);
// ERROR No viable conversion from 'std::__1::string aka 'basic_string<char, char_traits<char>, allocator<char> >') to 'DoctorType'
}
I'm expecting for it to compile because I am passing in a string into the Patient type which i think accepts strings.

Answer 1

The problem lies here:
void PatientType::setDrName(DoctorType drName)
Here, you expect to send a DoctorType parameter. However, in calling you use:
example.setDrName(drName); where drName is a string, not a DoctorType parameter.
The fix is obvious: either modify the prototype so as it accepts a string parameter or, in calling the method, give it a DoctorType parameter.

Answer 2

The issue is this function:
void PatientType::setDrName(DoctorType drName) {
Here, this function expects parameter of type DoctorType but you are passing std::string.
example.setDrName(drName); // drName is std::string. So, Type mismatch
There are numerous ways to solve this:
Option 1: Change the function signature to void PatientType::setDrName(const std::string &drName) {
Option 2: Less trivial but it works. Define a parameterised constructor in DoctorType accepting std::string as parameter.
Like this:
DoctorType::DoctorType(const std::string &name): name(name) { }
I think Option 2 is suitable in your scenario.
As rightly suggested by #t.niese, you must explicitly create the object of DoctorType and define constructor as explicit. Like this:
explicit DoctorType::DoctorType(const std::string &name): name(name) { }
and while calling it:
example.setDrName(DoctorType(drName));