Conditional constructor calling in C-CodePudding

In the following code

#include <iostream>

enum class motorid{
    M1,
    M2
};
enum class encoderid{
    E1,
    E2
};
class encoder{
public :
    encoder(encoderid eid):Eid(eid){}
private:
    encoderid Eid;
};
class motor{
    public:
    motor(motorid mid):Mid(mid){
        if(mid == motorid::M1){
            e(encoderid::E1);
        }
        e(encoderid::E2);
    }
    private:
    motorid Mid;
    encoder e;
}

I want to initialize encoder class with value based on value given to motor class from main, I don't want to expose the encoder details to main,but I am forced to give the encoder type also. How to achieve this? Since no heap is involved using new and creating object is not an option.

CodePudding user response：

Syntax would be:

motor(motorid mid):Mid(mid), e(mid == motorid::M1 ? encoderid::E1 : encoderid::E2)
{
}

For more complex case (or for readability), creating function might help:

encoderid create_encoderid(motorid mid)
{
    if (mid == motorid::M1){
        return encoderid::E1;
    }
    return encoderid::E2;
}

motor::motor(motorid mid):Mid(mid), e(create_encoderid(mid))
{
}