How to make this C++ code more DRY?

Question

I have these two methods on a class that differ only in one method call. Obviously, this is very un-DRY, especially as both use the same formula.

int PlayerCharacter::getAttack() {
    int attack;
    attack = 1 + this->level;
    for(int i = 0; i < this->current_equipment; i++) {
        attack += this->equipment[i].getAttack();
    }
    attack *= sqrt(this->level);
    return attack;
}
int PlayerCharacter::getDefense() {
    int defense;
    defense = 1 + this->level;
    for(int i = 0; i < this->current_equipment; i++) {
        defense += this->equipment[i].getDefense();
    }
    defense *= sqrt(this->level);
    return defense;
}

How can I tidy this up in C++?

Answer 1

One easy way is to represent all of a piece of equipment's attributes in an array, indexed by an enum.

enum Attributes {
  Attack, 
  Defense,
  AttributeMAX
};

class Equipment {
  std::vector<int> attributes;

  Equipment(int attack, int defense): attributes(AttributeMAX)
  {
    attributes[ATTACK] = attack;
    attributes[DEFENSE] = defense;
  }

};

Then you change your function to

int PlayerCharacter::getAttribute(int& value, Attribute attribute) {
    value = 1 + this->level;
    for(int i = 0; i <= current_equipment; i++) {
        value += this->equipment[i].attributes[attribute];
    }
    value *= sqrt(this->level);
    return value;
}

And you can call it like so

  player.getAttribute(player.attack, Attack);

Answer 2

In my opinion, what you have is fine, as it will allow you to tweak attack/defense more than if you represented both of them with one function. Once you start testing your game, you'll begin balancing attack/defense formulas, so having separate functions for them is fine.

The whole concept of DRY [don't repeat yourself] is [hopefully] to prevent your code from becoming a huge copy & paste fest. In your situation, the defense/attack formulas will change over time [for example, what if characters have buffs/status-ailment? A specific status ailment might cut defense in half, while increasing attack by 2 (Berserk, FF reference, heh)]