How to override abstract class constructor in sub class

manpreet Best Answer 3 years ago

Ive just moved from java to c++ and I'm really struggling with what were once basic concepts. All I want to do is create an abstract class called 'Spaceship', give it a constructor that takes 4 arguments, and then in a sub class called 'Alienspaceship', I want to make a constructor that takes 5 arguments but inherits the 'spaceship' constructors first 4 arguments. Ive been looking all over the place and can't seem to find exactly what I'm looking for. Below is my code. Please and thank you to anyone who can help me!

header

#ifndef SPACESHIP
#define SPACESHIP

#include "Enum.h"

class Spaceship{
    public:
    float health;
    float food;
    float cash;
    float misc;

public:
    Spaceship(float, float, float, float);

};

class AlienSpaceship: public Spaceship{
    OrganismType race;

    public:
        AlienSpaceship(float, float, float, float, OrganismType):Spaceship(float, float, float, float){}
};

#endif

cpp

#include "Spaceship.h"

Spaceship::Spaceship(float health, float food, float cash, float misc){
    this->health = health;
    this->food = food;
    this->cash = cash;
    this->misc = misc;
}

AlienSpaceship::AlienSpaceship(float health, float food, float cash, float misc, OrganismType race):Spaceship(health, food, cash, misc){
    this->race = race;
}

manpreet 3 years ago

You seem to misunderstand how the constructor initializer list works.

It's used in the definition (i.e. implementation) of the constructor, it's not needed for the declaration of your constructor.

In fact, your current declaration in the AlienSpaceship class actually defines (implements) the constructor, because of the ending {}.

So for the class, all you need to do is

class AlienSpaceship: public Spaceship{
    ...
    public:
        AlienSpaceship(float, float, float, float, OrganismType);
};