Programming Forums > Application Development > C++

aznballerlee · Nov 30th, 2006, 12:52 AM

Quote:

Does this look right to you? Why should your array for storing energy sources be limited to the maximum number of robots?

MAXSOURCES.

aznballerlee · Nov 30th, 2006, 1:07 AM

At this point, I'm still confused as to the storing array.
I don't know which is the private array, but I do know that is can hold MAXSOURCES elements.

The Dark · Nov 30th, 2006, 1:45 AM

(Toggle Plain Text)

bool Valley::addEnergySource(int r, int c)
{
	//      TODO: implement addEnergySource
	//      If MAXSOURCES have already been added, return false.  Otherwise,
	//      dynamically allocate a new energy source at coordinates (r,c).
	//      Save the pointer to the newly allocated energy source and return true.
	//      (Hint:  The Valley class could contain a private array with MAXSOURCES
	//      elements.)
	if (m_nsources == MAXSOURCES)
		return false;
	else
	{
		EnergySource* es = new EnergySource(r,c);
		return true;
	}
}

Quote:

Originally Posted by aznballerlee

Initially, m_nsources is 0. When we created the new EnergySource, a pointer is created to m_sources[m_nsource]. Once the source has been recorded in the array, we increment m_nsources. Repeatedly, when addEnergySource is called again and again, the m_nsources is incremented, until it exceeds the MAXSOURCES.

This is my problem.

What you need to do is to change the code in red to match the text in red. At the moment you are creating a new EnergySource, but then not doing anything with the resulting pointer.

Quote:

At this point, I'm still confused as to the storing array.
I don't know which is the private array, but I do know that is can hold MAXSOURCES elements.

The private array is m_sources - you already said that in your post above. The size of the m_sources private array in your original code was MAXROBOTS, which is not the same as MAXSOURCES.

aznballerlee · Nov 30th, 2006, 3:09 PM

Quote:

What you need to do is to change the code in red to match the text in red. At the moment you are creating a new EnergySource, but then not doing anything with the resulting pointer.

(Toggle Plain Text)

EnergySource* m_sources[m_nsource] = new EnergySource(r,c);
m_nsource++

Quote:

The private array is m_sources - you already said that in your post above. The size of the m_sources private array in your original code was MAXROBOTS, which is not the same as MAXSOURCES.

So would I need to add

(Toggle Plain Text)

EnergySource* m_sources[MAXSOURCES];

as a private array?

The Dark · Nov 30th, 2006, 5:59 PM

Quote:

Originally Posted by aznballerlee

(Toggle Plain Text)

EnergySource* m_sources[m_nsource] = new EnergySource(r,c);
m_nsource++

Almost - you don't need to redeclare m_sources as it is already in your Valley class. Delete the code in red.

Quote:

Originally Posted by aznballerlee

So would I need to add

(Toggle Plain Text)

EnergySource* m_sources[MAXSOURCES];

as a private array?

Umm, you already have done that in your Valley class. I assumed you knew that as you said you had modified the code to add it:
From your original code in the Valley class:

(Toggle Plain Text)

private:
	Robot*        m_robots[MAXROBOTS];
	int           m_nrobots;
	EnergySource* m_sources[MAXROBOTS];
	int           m_nsources;
};

aznballerlee · Nov 30th, 2006, 6:35 PM

I don't understand your suggestion:

Quote:

Umm, you already have done that in your Valley class. I assumed you knew that as you said you had modified the code to add it:
From your original code in the Valley class:
Code:

private: Robot* m_robots[MAXROBOTS]; int m_nrobots; EnergySource* m_sources[MAXROBOTS]; int m_nsources; };

So do I alter the one I add since it was wrong?

(Toggle Plain Text)

private:
	Robot*        m_robots[MAXROBOTS];
	int           m_nrobots;
	EnergySource* m_sources[MAXSOURCES];
	int           m_nsources;

The Dark · Nov 30th, 2006, 6:46 PM

Yes you altered the right one. The reason I did not know that you changed the right one is that I can't see your computer. I can only go by the code that you have posted.

My only suggestion was to remove the red bit of code in my last post. At the moment that code is declaring a new local array and then trying to assign a single value to it. It won't even compile. If you remove the red code that is declaring it (the "EnergySource*"), then the compiler will know to use the m_sources member variable from the class. This is what your teacher called a "private array".

aznballerlee · Nov 30th, 2006, 6:58 PM

Okay, I get that. My other problem is implementing this with Robots. I use the same logic:

(Toggle Plain Text)

bool Valley::addRobot(string name, vp, int r, int c, Dir dir)
{
	if (m_nrobots == MAXROBOTS)
		return false;
	else
	{
		m_robots[m_nrobots] = new Robot(name,    ,r, c, dir);
		return true;
	}
}

The compiler says vp is undeclared, which makes sense since I haven't done that other than in the constructor. How do I do this? I thought about using another accessor function or so to declare it .. and someone said to pass it through something whivch I have no clue how to do .

The Dark · Nov 30th, 2006, 7:06 PM

You don't need to pass vp into the addRobot function. The valley pointer can be found using the this keyword as you are in a Valley member function.

(Toggle Plain Text)

m_robots[m_nrobots] = new Robot(name, this, r, c, dir);

Also don't forget that you need to increment m_nrobots when you add a robot.

aznballerlee · Nov 30th, 2006, 7:16 PM

Alright, I get that.. when I'm done adding the stuff, I'll have to call the destructor to delete the new array.

Would this be appropriate?

(Toggle Plain Text)

//      TODO:  Implement the destructor
//      Delete any dynamically allocated objects held by the Valley.

Valley::~Valley()
{
	 delete [] m_robots ;
	 delete [] m_sources;
	
}

Nov 30th, 2006, 6:58 PM	#18
aznballerlee Hobbyist Programmer Join Date: Nov 2006 Posts: 111 Rep Power: 2	Okay, I get that. My other problem is implementing this with Robots. I use the same logic: (Toggle Plain Text) bool Valley::addRobot(string name, vp, int r, int c, Dir dir) { if (m_nrobots == MAXROBOTS) return false; else { m_robots[m_nrobots] = new Robot(name, ,r, c, dir); return true; } } bool Valley::addRobot(string name, vp, int r, int c, Dir dir) { if (m_nrobots == MAXROBOTS) return false; else { m_robots[m_nrobots] = new Robot(name, ,r, c, dir); return true; } } The compiler says vp is undeclared, which makes sense since I haven't done that other than in the constructor. How do I do this? I thought about using another accessor function or so to declare it .. and someone said to pass it through something whivch I have no clue how to do .

Nov 30th, 2006, 7:06 PM	#19
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	You don't need to pass vp into the addRobot function. The valley pointer can be found using the this keyword as you are in a Valley member function. (Toggle Plain Text) m_robots[m_nrobots] = new Robot(name, this, r, c, dir); m_robots[m_nrobots] = new Robot(name, this, r, c, dir); Also don't forget that you need to increment m_nrobots when you add a robot.

Nov 30th, 2006, 7:16 PM	#20
aznballerlee Hobbyist Programmer Join Date: Nov 2006 Posts: 111 Rep Power: 2	Alright, I get that.. when I'm done adding the stuff, I'll have to call the destructor to delete the new array. Would this be appropriate? (Toggle Plain Text) // TODO: Implement the destructor // Delete any dynamically allocated objects held by the Valley. Valley::~Valley() { delete [] m_robots ; delete [] m_sources; } // TODO: Implement the destructor // Delete any dynamically allocated objects held by the Valley. Valley::~Valley() { delete [] m_robots ; delete [] m_sources; }

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Wierd compile Error. Need help please.	Keiyentai	Java	7	Aug 19th, 2006 1:35 AM
What is: "Oriented programming (OO)?"	BrinyCode	C++	12	Nov 22nd, 2005 7:40 AM
Java programmers, game developers, artists, be ware! RPG game team is recruiting!	atcomputers.us	Paid Job Offers	7	Sep 25th, 2005 7:25 PM
User Input for Number Format	ericelysia1	Java	0	Jul 21st, 2005 3:41 PM
Programmers Needed! Online Game	troy_eisert	C++	2	Jan 29th, 2005 12:51 PM

Nov 30th, 2006, 1:07 AM	#12
aznballerlee Hobbyist Programmer Join Date: Nov 2006 Posts: 111 Rep Power: 2	At this point, I'm still confused as to the storing array. I don't know which is the private array, but I do know that is can hold MAXSOURCES elements.

Nov 30th, 2006, 6:46 PM	#17
The Dark Expert Programmer Join Date: Jun 2005 Posts: 810 Rep Power: 4	Yes you altered the right one. The reason I did not know that you changed the right one is that I can't see your computer. I can only go by the code that you have posted. My only suggestion was to remove the red bit of code in my last post. At the moment that code is declaring a new local array and then trying to assign a single value to it. It won't even compile. If you remove the red code that is declaring it (the "EnergySource*"), then the compiler will know to use the m_sources member variable from the class. This is what your teacher called a "private array".

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Programming Forums > Application Development > C++

Game: Robot (Class, Constructors)