Elysian Shadows

Posted: **Sun Jul 04, 2010 10:23 pm**

Hello guys. So, I have a problem involving something that is over my head which inevitably has forced me to ask questions. I have a player class and a weapon class and for a while I've been trying to figure out how to make the first tie in with the latter using class inheritance. I've solved that but have run into something. I want my player class to be able to automatically draw/use information from the weapon class based on the current weapon the player has equipped. Take for example:

Real code mixed with pseudo code.

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player.pCurrWeap.SetCurrWeap(Glock);

In my player.h file I declared Weapon pCurrWeap; as a public member.

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Glock.clipSize = 17; 
cout << player.pCurrWeap.GetClipSize(); << endl;

I want it to tell me the ammo information which in this case is the amount of ammo in the Glock gun that is equipped without me having to set it using a function. Obviously, I would set all the variable information for the Glock weapon beforehand like say I made Glock a derived class of Weapon (which I wouldn't).

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class Glock : public Weapon
{
private:
           //all the information for the gun
public:
          Glock(); 
          ~Glock();
} 

Glock::Glock()
{
    x = 100;
    y = 100;
    //etc. 
}

Well I'm sure your ways of doing it would probably involve vectors and pointers, a change up of the class for better inheritance...whatever you choose. I'd just really like to get past the stumbling block. I was also wondering whether or not I should make a vector for weapons but am not sure how I'd use that and work that in to use this. Like this:

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player.pCurrWeap(vector<Weapon> currWeap).GetClipSize() //get clip size for currently equipped weapon

Not sure if I can even do this.

Anyways, thanks for your help.

Posted: **Mon Jul 05, 2010 5:12 am**

Hey there. I'm not completely sure I understand what you need but I hope this is what you meant. Good luck.

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#include <iostream>

enum WeaponType {
    GLOCK
};


class Weapon {
private:
    WeaponType _type;
    unsigned int _clipSize;

public:
    Weapon(WeaponType type, unsigned int clipSize) : _type(type),
                                                     _clipSize(clipSize) {}

    ~Weapon() {}

    unsigned int getClipSize() {
        return (_clipSize);
    }

    WeaponType getType() {
        return (_type);
    }
};


class Glock : public Weapon {
public:
    Glock() : Weapon(GLOCK, 16) {}
    ~Glock() {}
};


class Player {
private:
    Weapon* _weapon;

public:
    Player() : _weapon(0) {}

    ~Player() {
        delete _weapon;
    }

    void setWeapon(WeaponType type) {
        if (_weapon != 0) {
            if (_weapon->getType() == type) {
                return;
            }

            delete _weapon;
            _weapon = 0;
        }

        switch (type) {
            case GLOCK: _weapon = new Glock;
                        break;
        }
    }

    void printOutClipSizeOfCurrentWeapon() {
        if (_weapon != 0) {
            std::cout << "Clip size: " << _weapon->getClipSize() << "\n";
        } else {
            std::cout << "You aren't wielding a weapon dikhed!\n";
        }
    }
};

Posted: **Mon Jul 05, 2010 10:44 am**

Thanks for replying. Two hours after doing my initial post, I figured it out and then two hours after that I ran into a problem again. Hopefully, I can use your code to help figure out my problem. I'll re-explain my problem just in case others would like to give it a try but what you have looks goods.

Example:

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Weapon Glock(14); //An instance of the Weapon class and the first parameter of the constructor is wClipSize.
player.pCurrWeap.SetCurrWeap(Glock); 
player.pCurrWeap.GetClipSize(); //Tells me the current clip size of the currently equipped weapon

Instead of me having to do:

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Weapon Glock(14)
player.pCurrWeap.SetCurrWeap(Glock);
player.pCurrWeap.GetClipSize(Glock);

This is pseudo code but I wouldn't work cause the weapon the player holds is likely to be constantly changing when he picks up and drops a weapon. So I can't manually always have to put it in. Doing it this way would probably make me have to do something like this:

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if (player.pCurrWeap = Glock)
{
     //find out the weapon information for glock; 
}

And do that for every single weapon in the game.
What I did to get it to work is this (very messy, unprofessional code):

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//main.cpp
    Weapon Standard; 
    Standard.SetClipSize(17); 
    Standard.SetBulletDmg(4);

    player.pCurrWeap.GiveWeap(Standard);

    cout << player.pCurrWeap.GetClipSize() << endl;
    cout << player.pCurrWeap.GetBulletDmg() << endl;

//weapon.cpp
int Weapon::GetClipSize() 
{
    Weapon currWeap; //notice I have to declare this in both the Get functions. This is causing my next problem.
    return currWeap.wClipSize; 
} 
void Weapon::SetBulletDmg(int bulletDmg)
{
     wBulletDmg = bulletDmg;
}
int Weapon::GetBulletDmg()
{
       Weapon currWeap;
       return currWeap.wBulletDmg;
}
void Weapon::GiveWeap(Weapon currWeap) 
{ 
Weapon pCurrWeap = currWeap; 
}

The problem I'm having now is that when in main.cpp, I have to state this:

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player.pCurrWeap.GiveWeap(Standard);

before every get function I have or else it wont work. Like, It would work for the first get function because I declared that once but it wont work for the second unless I put that line of code in again.

Posted: **Mon Jul 05, 2010 11:52 am**

Why are you giving your weapons to your weapons?

Posted: **Mon Jul 05, 2010 12:18 pm**

I have no idea except that I thought that in order for pCurrWeap to equal something, It would have to equal a Weapon variableexample;. I'm not sure what I should give it to? Should I declare a variable in my weapon class to take it?

Posted: **Mon Jul 05, 2010 2:09 pm**

Is this what you mean?

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class Weapon
{
public:
      Weapon(int csize) {clipsize=csize;}
      Weapon() {}
      void SetWep(Weapon*wep) { *this=*wep;}
      void SetDamage(int d){damage=d;}
      int GetClipSize(){return clipsize;}
      ~Weapon(){}
protected:
      int clipsize,damage;
};

class Player
{
public:
Weapon CurrentWep;
};

int main()
{
Weapon Glock(16);
Player P;
P.CurrentWep.SetWep(&Glock);
std::cout<<P.CurrentWep.GetClipSize()<<"\n"; //this will print 16, i tested it
}

Posted: **Mon Jul 05, 2010 2:47 pm**

Works perfectly MV, thanks a lot! To think, I was making it a lot more complicated than it called for.

Posted: **Mon Jul 05, 2010 4:10 pm**

TheLividePianoist wrote:Works perfectly MV, thanks a lot! To think, I was making it a lot more complicated than it called for.

Yes, you just needed to include a pointer to a Weapon in your Player class :P

Posted: **Mon Jul 05, 2010 4:47 pm**

xiphirx wrote:
TheLividePianoist wrote:Works perfectly MV, thanks a lot! To think, I was making it a lot more complicated than it called for.
Yes, you just needed to include a pointer to a Weapon in your Player class :P

Actually he had a weapon in his player class, but he wasnt setting it's values correctly.
*this=wep

Posted: **Mon Jul 05, 2010 4:52 pm**

Only suggestion I'll add is to have the SetWep function take a reference or pointer, rather than a copy. Optimizations ftw?

Posted: **Mon Jul 05, 2010 4:55 pm**

XianForce wrote:Only suggestion I'll add is to have the SetWep function take a reference or pointer, rather than a copy. Optimizations ftw?

touche, edited the code i posted

Posted: **Mon Jul 05, 2010 6:27 pm**

Thanks more but can someone explain to me the reason for the pointers and or other stuff you added. What exactly does it do?

Posted: **Mon Jul 05, 2010 6:45 pm**

TheLividePianoist wrote:I have no idea except that I thought that in order for pCurrWeap to equal something, It would have to equal a Weapon variableexample;. I'm not sure what I should give it to? Should I declare a variable in my weapon class to take it?

It would make more sense to set your current Weapon to another using a method in your Player class. This was demonstrated in the code that X Abstract X posted.

Have you Googled "pointers" and searched the forums first?

Posted: **Mon Jul 05, 2010 7:01 pm**

TheLividePianoist wrote:Thanks more but can someone explain to me the reason for the pointers and or other stuff you added. What exactly does it do?

I'm going to assume this question is about the parameter change to reference or pointer.

So basically, anytime you pass a variable as a parameter, your not actually passing that variable. Your just passing a copy of that variable.

So here's a quick example to demonstrate:

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void function(int x)
{
     x = 3;
     std::cout << x << std::endl;
}

int main()
{
     int x = 2;
     std::cout << x << std::endl;

     function(x);

     std::cout << x << std::endl;

     return 0;
}

So at first glance, you'd probably expect the output to look something like:

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2
3
3

Which makes sense considering we assigned the value of 3 to x in function(int x). Too bad we didn't actually pass x, we passed 2. So the output should actually be:

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2
3
2

After function ends, the variable x that was set to 3 is removed from the stack. This whole idea is commonly known as passing by value.

So let's say you wanted to actually change the value of x, you can solve this by passing a pointer or reference to the object, rather than the object itself.

This means, a new object won't be created just to pass a parameter (which will probably give some undesired results in many cases anyways).

So it's more efficient to use references/pointers when passing objects, not too sure about primitive types (int, char, bool, float, etc).

Hope that helps.

Elysian Shadows

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