[Solved] Question on class object

[dandymcgee]

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#include <iostream>
#include <string>
using namespace std;

class Weapon
{
	public:
		void dispWeapon();
	private:
		string weapName;
	protected:
};

void Weapon::dispWeapon()
{
	weapName = "knife";
	cout << weapName << endl;
}

class Character
{
	public:
		void aFunc();
	private:
		Weapon weapon;
	protected:
};

void Character::aFunc()
{
	cout << "aFunc\n";
}

int main()
{
	Character character;

	character.aFunc();

	character.weapon.dispWeapon();   //I know this is wrong but how am I supposed to access
							               //class Weapon through class Character
	return 0;
}

error C2248: 'Character::weapon' : cannot access private member declared in class 'Character'
see declaration of 'Character::weapon'
see declaration of 'Character'

This:

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character.weapon.dispWeapon(); 

isn't legal because you defined weapon as private. Move the "Weapon weapon;" declaration to Character's public members and it will work just fine. If you want to leave it in private then you need to make an accessor (which would probably end up returning a pointer to weapon that you could then use to make function calls).

[zodiac976]

I know about declaring them and declaring them in
separate header files, thanks though.

[dandymcgee]

I know about declaring them and declaring them in
separate header files, thanks though.

Please re-read.. I completely edited because you posted at the same time as me.

[zodiac976]

I know about declaring them and declaring them in
separate header files, thanks though.

Please re-read.. I completely edited because you posted at the same time as me.

sorry about that. Something like this?;
it actually worked...:

Code: Select all

#include <iostream>
#include <string>
using namespace std;

class Weapon
{
	public:
		void dispWeapon();
	private:
		string weapName;
	protected:
};

void Weapon::dispWeapon()
{
	weapName = "knife";
	cout << weapName << endl;
}

class Character: public Weapon
{
	public:
		void aFunc();
		void setWeapon(Weapon temp) {weapon = temp;}
		Weapon getWeapon() const {return weapon;}
	private:
		Weapon weapon;
	protected:
};

void Character::aFunc()
{
	cout << "aFunc\n";
}

int main()
{
	Character character;

	character.aFunc();

	character.getWeapon().dispWeapon();

	return 0;
}

I am assuming I did it right I guess....

[dandymcgee]

sorry about that. Something like this?;
it actually worked...:

Code: Select all

I am assuming I did it right I guess.... :|[/quote]
Yup, that looks about right.  If it compiled then I suppose it works.   ;)

[zodiac976]

sorry about that. Something like this?;
it actually worked...:

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I am assuming I did it right I guess.... :|[/quote]
Yup, that looks about right.  If it compiled then I suppose it works.   ;)[/quote]

It does work and displays what's inside the functions
hmm weird I have never gotten around to this if this
stuff is super common...:(. Thanks though I believe
I got this down now.

[MarauderIIC]

Code: Select all

class Character: public Weapon
{
	public:
		void aFunc();
		void setWeapon(Weapon temp) {weapon = temp;}
		Weapon getWeapon() const {return weapon;}
	private:
		Weapon weapon;
	protected:
};

No. You're saying a character is a weapon and a character has a weapon. You want only one of these relationships.

"class Character : public weapon" = "Character IS A weapon"
"class Character { /* ... */ Weapon weapon; /* ... */ };" = "Character HAS A weapon

Further, you write,

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		Weapon getWeapon() const {return weapon;}

This is bad because it makes a copy of the weapon and returns it. You don't want to make a copy, this is slow. Return a const reference or a const pointer. You might be returning a const copy, I'm not sure, I have to brush up on the different locations of the const keyword. I think declaring the function as

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Weapon& getWeapon() const /* ... */

will give you a const reference.