Static map to function pointers - c++

Question

I am trying to implement something similar to C# setters in C++. The idea is to have an enum of class properties and the corresponding setters. My code looks as follows. I will write the implementation in the class definition.
#include <string>
#include <map>
enum ClassProperties
{
Id, Name
};
class MyClass
{
public:
int Id;
std::string Name;
public void SetValue(ClassProperties c, std::string value){
setters[c](this, value);
}
private:
typedef void (* t_setter)(MyClass *, std::string);
static void set_id(MyClass * obj, std::string value) {
obj->Id = std::stoi(value);
}
static void set_name(MyClass * obj, std::string value) {
obj->Name = value;
}
static std::map<ClassProperties, t_setter> setters = {{ClassProperties:: Id, set_id}, {ClassProperties::Name, set_name}};
};
I'd expect this code to choose the cooresponding function and call it, but I get an error on the last line
error: in-class initialization of static data member ‘std::map<ClassProperties, void (**)(MyClass*, std::basic_string<char>)> MyClass::setters’ of incomplete type
error: could not convert ‘{{Id, MyClass::set_id}, {Name, MyClass::set_name}}’ from ‘<brace-enclosed initializer list>’ to ‘std::map<ClassProperties, void (**)(MyClass*, std::basic_string<char>)>’
What am I doing wrong?

Answer 1

Your initialization of setters is wrong. You should change it as follows:
1) Remove the line from the class body:
static std::map<ClassProperties, t_setter> setters =
{{ClassProperties:: Id, set_id}, {ClassProperties::Name, set_name}};
2) Add appropriate initialization of static member out of the class body:
std::map<ClassProperties, MyClass::t_setter> MyClass::setters = {
{ ClassProperties::Id, &MyClass::set_id },
{ ClassProperties::Name, &MyClass::set_name }
};
Besides, you have to remove public specifier before SetValue function.
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