Question

I’m trying to create a very simple turn-based text RPG game. The code compiles and runs but the attack and heal functions don’t seem to change the values of the variables. I’m pretty sure it’s a problem related to inheritance but I’m not sure.

#include <iostream>
#include <cstdlib>
#include <string>

using namespace std;

struct Stats {
       int hp;
       int def;
       int atk;
       int skl;
};

class Character {
      public:
             Character();
             virtual void getHit(int) = 0;
             int attack(int);
             void defend();
             virtual int getHP() = 0;

      protected:
              Stats m_Stats;
};

Character::Character() {
   m_Stats.hp = 0;
   m_Stats.def = 0;
   m_Stats.atk = 0;
   m_Stats.skl = 0;
}

int Character::attack(int def) 
{
    return (m_Stats.atk - def);
}


class Player : public Character {
      public:
             Player();
             void getHit(int);
             void healSelf();
             void fireBall();
             int getAtk();
             int getHP();
};

Player::Player()
{
     m_Stats.hp = 100;
     m_Stats.atk = 30;
     m_Stats.def = 10;
     m_Stats.skl = 10;     
}

int Player::getHP()
{
    return m_Stats.hp;
}

int Player::getAtk()
{ return m_Stats.atk; }

void Player::getHit(int atk)
{
   m_Stats.atk += m_Stats.def - atk;     
 }

void Player::healSelf()
{
     m_Stats.hp += m_Stats.skl;
     if(m_Stats.hp > 100)
        m_Stats.hp = 100;
}


class Enemy : public Character {
      public:
             Enemy();
             void getHit(int);
             void chooseAction();
             void rage();
             int choose();
             void defend();
             void resetAtk();
             int getAtk();
             int getHP();
};

Enemy::Enemy()
{
     m_Stats.hp = 150;
     m_Stats.atk = 40;
     m_Stats.def = 5;
     m_Stats.skl = 5;
}

int Enemy::getHP()
{
    return m_Stats.hp;
}

int Enemy::getAtk()
{
     return m_Stats.atk;
}

void Enemy::resetAtk()
{
     m_Stats.atk = 40;
}

int Enemy::choose()
{
     srand(time(0));
     int c = rand() % 3;
     if(c == 0)
        cout << "Enemy chooses to attack!\n";
     else if(c == 1)
        cout << "Enemy is raging!\n";
     else if(c == 2)
        cout << "Enemy chooses to defend!\n";
     return c;
}

void Enemy::rage()
{
     m_Stats.atk += 3;
 }

void Enemy::getHit(int atk)
{
   m_Stats.atk += m_Stats.def - atk;   
   m_Stats.def = 5;  
}

void Enemy::defend()
{
     m_Stats.def += 2;
}


int main()
{
    Player p;
    Enemy e;
    bool done = false; int choice, move;
    cout << "The enemy faces you!\n";
    while(!done)
    {cout << "1) Attack  2) Heal Self. ";
     cin >> choice;
     if(choice == 1)
      {  e.getHit(p.getAtk());}
     else if(choice == 2)
        {p.healSelf(); }

     cout << "Your HP: " << p.getHP() << "\n";
     cout << "Enemy HP: " << e.getHP() << "\n";

     choice = e.choose();
     if(choice == 1)
         {p.getHit(e.getAtk());
         e.resetAtk();
         }
     else if(choice == 2)
         e.rage();
     else if(choice == 3)
         e.defend();

     cout << "Your HP: " << p.getHP() << "\n";
     cout << "Enemy HP: " << e.getHP() << "\n";


     if(p.getHP() == 0 || e.getHP() == 0)
         done = true;
     }

     if(p.getHP() > e.getHP())
         cout << "You won!" << endl;
     else
         cout << "You lost!" << endl;


    system("PAUSE");
    return 0;
}

sample output

The enemy faces you!
1) Attack  2) Heal Self. 1
Your HP: 100
Enemy HP: 150
Enemy chooses to defend!
Your HP: 100
Enemy HP: 150
1) Attack  2) Heal Self: 2
Your HP: 100
Enemy HP: 150

Yeah, the output is not pretty but I’m putting off clearing up output after the code is solid. Any help would be appreciated. Thanks.

Answer 1

Why would you expect these values to change? The only place in your program where you change the value of hp field is the Player::healSelf method. Since the player’s HPs are capped at 100, and the player has 100 HP from the beginning, calling healSelf cannot rise the hp value above 100. This is why it doesn’t change.

I would expect your getHit methods to change the hp value of player and enemy. But they don’t. See for yourself

void Enemy::getHit(int atk)
{
   m_Stats.atk += m_Stats.def - atk;   
   m_Stats.def = 5;  
}

There’s no mention of hp in that code. Apparenty, it is a bug. The same bug seems to be present in Player::getHit implementation.