C++ Inheritance of functions, passing in arguments - c++

Question

Base class : Employee
Derived class : Regular
Employee.cpp
void Employee::setValue(string id, string name, double s, int n)
{
empID = id;
empName = name;
salary = s;
}
Regular.cpp
void Regular::setValue(string id, string name, double s, int n)
{
annualLeave = n;
}
Employee::setValue() only stores the first 3 arguments passed in, but not int n, too.
I'm supposed to inherit that setValue() in Regular::setValue() and then just pass in the arguments, but this time store int n to annualLeave.
How do I do that?
Or, is there a way for me to set int n in the base class for the child class?

Answer 1

You can call the base class's implementation:
void Regular::setValue(string id, string name, double s, int n) {
annualLeave = n;
return Employee::setValue(std::move(id), std::move(name), s);
}
Otherwise, make base class polymorphic:
struct Employee {
void setValue(string id, string name, double s, int n) {
empID = std::move(id);
empName = std::move(name);
salary = s;
setLeave(n);
}
virtual ~Employee() {}
protected:
virtual void setLeave(int) = 0;
string empID;
string empName;
double salary;
};
struct Regular: Employee {
private:
void setLeave(int n) override { annualLeave = n; }
int annualLeave;
};

Answer 2

If necessary to keep a single-signature setValue function, it is possible to do it like that:
-
Includes:
#include <any>
#include <map>
#include <string>
-
Employee.h:
class CEmployee
{
protected:
virtual void setValue(std::map<std::string, std::any> &info);
int m_empID = 0;
std::string m_empName = {'\0'};
int m_salary = 0;
}
Employee.cpp:
void CEmployee::setValue(std::map<std::string, std::any> &info)
{
std::any item;
item = info["empID"];
if (item.has_value())
m_empID = std::any_cast<int>(item); // int
item = info["empName"];
if (item.has_value())
m_empName = std::any_cast<std::string>(item); // std::string
item = info["salary"];
if (item.has_value())
m_salary = std::any_cast<int>(item); // int
}
-
Regular.h:
class CRegular : public CEmployee
{
public:
void setValue(std::map<std::string, std::any> &info) override;
protected:
std::string m_annualLeave = {'\0'};
}
Regular.cpp:
void CRegular::setValue(std::map<std::string, std::any> &info)
{
std::any item;
CEmployee::setValue(info);
item = info["annualLeave"];
if (item.has_value())
m_annualLeave = std::any_cast<std::string>(item); // std::string
}
-
& call it like that:
void MyClass::HardcodedExample()
{
CRegular regular_employee;
std::map<std::string, std::any> info, update;
info["empID"] = { 100 };
info["empName"] = { std::string("Trump") };
info["salary"] = { 1000000 };
info["annualLeave"] = { std::string("29 Jul 2018") };
regular_employee.setValue(info); // Set all info
// Or:
update["annualLeave"] = { std::string("29 Dec 2018") };
regular_employee.setValue(update); // Update just "annualLeave"
// Or:
update["salary"] = { 1200000 };
update["annualLeave"] = { std::string("04 Jul 2018") };
regular_employee.setValue(update); // Update "salary" & "annualLeave"
}
-
Otherwise, setValue with 3 parameters to base-class, & with 4 parameters to the derived-class (that calls to the base-class with the 3 parameters and sets by itself the 4th one) - similar to what #RemyLebeauis offers - is a better solution.
-
& better to use #define / enum keys instead of string-keys (& change the key-type of the map accordingly), but this is a different issue.