damage algorithm for simple game

[levilone]

I'm having issues calculating damage from a small game I wrote. Every time the player or enemy attack, the damage gets reset so no one ever dies. The problem is in character::hp in characters.cpp.

characters.h

#ifndef RESOURCES_H
#define RESOURCES_H

class Die{
public:
	static int roll();
};

class character{
public:
	static int hp();
	bool state();
};

class attack{
public:
	int number();
};

#endif 

characters.cpp

#include <iostream>
#include <cstdlib>
#include <ctime>
#include "characters.h"

int damage;

int Die::roll()
{
	return rand()%4+1;
}

int character::hp()
{
	int initialhealth=500;
	int health = initialhealth-damage;
	int currenthealth = health-damage;
	return currenthealth;
}

int attack::number()
{
	damage=(rand()%4+1) * 25;
    return damage;
}

main.cpp

#include <iostream>
#include "characters.h"

int main()
{
	srand(time(0));
	char select;
	character player;
	character troll;
	std::cout << "Hello, welcome to wizardworld version 1" << std::endl;
	std::cout << "there is a troll in the room you are in, engage in combat?" << std::endl;
	
	std::cout << "Both your hp, and the troll's hp start at 500, you will take turns attacking each other until one of you runs out" << std::endl;
	std::cout << "the players hp is " << player.hp() << std::endl;
	std::cout << "the troll's hp is " << troll.hp() << std::endl;
	
	while(player.hp()>0 and troll.hp()>0)
	{
	std::cout << "enter a to begin combat" << std::endl;
	std::cin >> select;
	if(select=='a')
	std::cout << "You have entered combat" << std::endl;
	else return 0;
	
	
	player.hp(); 
	attack theplayer;
	attack thetroll;
	
	std::cout << "to attack enter a" << std::endl;
	std::cin >> select;
	if(select=='a'){
	thetroll.number();
	std::cout << troll.hp() << std::endl;
	}
	else return 0;
	
	std::cout << "it is the trolls turn to attack" << std::endl;
	theplayer.number();
	std::cout << "the troll attacked, your hp is now " << player.hp() << std::endl;
	}
	if(troll.hp()>0)
	std::cout << "The troll has won." << std::endl;
	else std::cout << "You have Won!!!" << std::endl;
	return 0;
}

[Computergeek01]

This is because "initialhealth" is a variable that is local to that member function 'hp()' when it should be a private member of the class 'character' and set at the constructor.

EDIT: Also "damage" should be an argument passed to 'hp()', not a global variable.

[levilone]

alright, I moved initialhealth to characters.cpp as a private member
now i get terminal error

characters.cpp: In static member function ‘static int character::hp()’:
characters.cpp:15:15: error: invalid use of member ‘character::initialhealth’ in static member function
   15 |  int health = initialhealth-damage;
      |               ^~~~~~~~~~~~~
In file included from characters.cpp:4:
characters.h:13:6: note: declared here
   13 |  int initialhealth=500;

also, I don't know how to pass damage as an argument yet, so first I'm going to focus on resolving the error.
characters.cpp

#include <iostream>
#include <cstdlib>
#include <ctime>
#include "characters.h"

int damage;

int Die::roll()
{
	return rand()%4+1;
}

int character::hp()
{
	int health = initialhealth-damage;
	int currenthealth = health-damage;
	return currenthealth;
}

int attack::number()
{
	damage=(rand()%4+1) * 25;
    return damage;
}

characters.h

#ifndef RESOURCES_H
#define RESOURCES_H

class Die{
public:
	static int roll();
};

class character{
public:
	static int hp();
	private:
	int initialhealth=500;
};

class attack{
public:
	int number();
};

#endif 

[seeplus]

How are learning C++? What book etc are you using? For an on-line resource I suggest https://www.learncpp.com/

[levilone]

I've been following tutorials and assigning myself projects like this game. I've learned at least as much coding this game as from the tutorials. I currently have no books. I followed the tutorials from thecpluplus guy on YouTube, which I find easy to follow. But yeah, it's going to take a while to develop a breadth of knowledge. I started learning about a week ago.

Every so often I run into a problem I can't easily solve in an hour or two, so I make a post. I try not to over rely on it. I've learned a lot about classes and member functions compared to when I started this project and I have a plan to make a larger terminal based game by expanding this one in multiple iterations.

[Computergeek01]

The 'hp()' member function doesn't NEED to be static here. You're also missing the time.h header.

EDIT:

character.cpp should read more like this:

#include <iostream>
#include <cstdlib>
#include <ctime>
#include "character.hpp"

//int damage;

int Die::roll()
{
	return rand()%4+1;
}

int character::hp(int damage)
{
	//int health = initialhealth-damage;
	health = health-damage;
	return health;
}

int attack::number()
{
	//damage=(rand()%4+1) * 25;
    int dmg = (rand()%4+1) * 25;
    return dmg;
}

I've renamed the member variable "initialhealth" to just "health" since that appears to have been tripping you up.

EDIT 2: There's actually a lot to change now that I've tried to compile it. But it's small stuff. Let me see if I can help out.

[levilone]

So, basically I couldn't get this to compile without the global variable damage. here's my current errors after changing to the above

characters.cpp:13:5: error: no declaration matches ‘int character::hp(int)’
   13 | int character::hp(int damage)
      |     ^~~~~~~~~
In file included from characters.cpp:4:
characters.h:11:13: note: candidate is: ‘static int character::hp()’
   11 |  static int hp();
      |             ^~
characters.h:9:7: note: ‘class character’ defined here
    9 | class character{
      |       ^~~~~~~~~
characters.cpp: In member function ‘int attack::number()’:
characters.cpp:21:2: error: ‘damage’ was not declared in this scope
   21 |  damage=(rand()%4+1) * 25;

characters.cpp

#include <iostream>
#include <cstdlib>
#include <ctime>
#include "characters.h"

//int damage;

int Die::roll()
{
	return rand()%4+1;
}

int character::hp(int damage)
{
	health = health-damage;
	return health;
}

int attack::number()
{
	damage=(rand()%4+1) * 25;
    return damage;
}

edit: changes to characters.h

#ifndef RESOURCES_H
#define RESOURCES_H

class Die{
public:
	static int roll();
};

class character{
public:
	static int hp();
	private:
	int health=500;
};

class attack{
public:
	int number();
};

#endif 

[Computergeek01]

Like I said, there was a bunch of small things. Take what you have and save it to another folder. Start a new project and try this, I've kept the changes to a minimum:

character.hpp:

#ifndef CHARACTER_HPP_INCLUDED
#define CHARACTER_HPP_INCLUDED
class Die{
public:
	static int roll();
}; //NOT USED

class character{
public:
    character(): health(500) {};

	int hp(int);
	int hp();
	int attack();
	private:
	int health;
};

/*class attack{
public:
	int number();
};*/


#endif // CHARACTER_HPP_INCLUDED 

character.cpp:

#include <iostream>
#include <cstdlib>
#include <ctime>
#include "character.hpp"

//int damage;

int Die::roll() //NOT USED
{
	return rand()%4+1;
}

int character::hp()
{
    return health;
}

int character::hp(int damage)
{
	//int health = initialhealth-damage;
	health = health-damage;
	return health;
}


int character::attack()
{
	int dmg=(rand()%4+1) * 25;
    return dmg;
}

/*int attack::number()
{
	damage=(rand()%4+1) * 25;
    return damage;
}*/

main.cpp

#include <iostream>
#include "character.hpp"

int main()
{
	//srand(time(0));
	char select;
	character player;
	character troll;
	std::cout << "Hello, welcome to wizardworld version 1" << std::endl;
	std::cout << "there is a troll in the room you are in, engage in combat?" << std::endl;

	std::cout << "Both your hp, and the troll's hp start at 500, you will take turns attacking each other until one of you runs out" << std::endl;
	std::cout << "the players hp is " << player.hp(troll.attack()) << std::endl;
	std::cout << "the troll's hp is " << troll.hp(player.attack()) << std::endl;

	while(player.hp()>0 and troll.hp()>0)
	{
	std::cout << "enter a to begin combat" << std::endl;
	std::cin >> select;
	if(tolower(select)=='a')
	std::cout << "You have entered combat" << std::endl;
	else return 0;


	player.hp();
//	attack theplayer;
//	attack thetroll;

	std::cout << "to attack enter a" << std::endl;
	std::cin >> select;
	if(tolower(select)=='a'){
//	thetroll.number();
    player.hp(troll.attack());
	std::cout << troll.hp() << std::endl;
	}
	else return 0;

	std::cout << "it is the trolls turn to attack" << std::endl;
//	theplayer.number();
    troll.hp(player.attack());
	std::cout << "the troll attacked, your hp is now " << player.hp() << std::endl;
	}
	if(troll.hp()>0)
	std::cout << "The troll has won." << std::endl;
	else std::cout << "You have Won!!!" << std::endl;
	return 0;
}

Your damage isn't random though

Also, feel free to ask any questions.

[levilone]

That worked, thanks. Now I'm going to go through and figure out why these practices were better. Also, while playing the game, the damage appeared to be semirandom, as I would receive between 25 and 100 points in damage each turn, can you clarify what you meant. Is it just not truly random, or will I get the same results every time?

edit: Die::roll is a legacy. I started by modifying a dice rolling program. That's the only reason it was there.

[Computergeek01]

It's because I commented out "srand()" because time.h wasn't included but when I went through to compile and make my fixes I glazed over it. For something like this srand\rand is good enough. But something to keep in the back of your mind is that there are way better methods these days.

[levilone]

is the return value of dmg going to int hp(int damage); ?

[Computergeek01]

Yes, that is occurring on Lines 34 and 41 in Main.cpp.

[levilone]

Oh, that makes sense. I can fix it too then. But yes, I've been hearing that. I'll get up to date on random number generation eventually, for now my needs are very simple. I want to focus on mastering classes, member functions and constructors really.

[levilone]

That's clever. I find that while tutorials are nice, they don't seem to beat experience like this. Projects teach how to actually use whats in the tutorials. Thanks for the help!