Debug Assertion Error

Hello, I would very much appreciate any help. I'm a new programmar. I'm tring to make a text game and I Keep getting a Debug Assertion Error at runtime. Can Someone Please Help me know why and how to fix it. Thank you.

Code:

---

#include <string>
using namespace std;
class Space
{
public:

private:
string Description;
};

class Player
{
public:
Space **Location;
private:

};


int main(){
Player Anthony;
Space A[10][10];
Anthony.Location=(Space**)A ; // I think this part is causing the
for ( int i = 0 ; i < 10 ; i++ ){    // error
Anthony.Location[i] = A[i] ;
}




return 0;
}

---

>Anthony.Location=(Space**)A ;
If you have to use a cast, you're probably doing something suspicious. By the way, Space** isn't the same as a two dimensional array of Space. If you really wanted to do it this way, you could do this:

Code:

---

#include <iostream>
#include <string>

using namespace std;

class Space {
public:
  int Description;
};

class Player {
public:
  Space (*Location)[10];
};

int main()
{
  Space A[10][10];
  Player Anthony;

  Anthony.Location = A;
  for ( int i = 0; i < 10; i++ ) {
    for ( int j = 0; j < 10; j++ )
      Anthony.Location[i][j].Description = i + j;
  }

  for ( int i = 0; i < 10; i++ ) {
    for ( int j = 0; j < 10; j++ )
      cout<< Anthony.Location[i][j].Description <<' ';
    cout<<endl;
  }
}

---

But I wouldn't recommend it for anything but a toy that prints a nifty figure.

Well the cast rather gives it away. A pointer to a pointer (**) is not the same thing as a 2D array. Sure you can use [row][column] to access either, but that is where the similarity ends.

Try this

Code:

---

#include <string>
using namespace std;
class Space
{
public:

private:
string Description;
};

class Player
{
public:
Space (*Location)[10];  // a pointer to an array
private:

};


int main(){
    Player Anthony;
    Space A[10][10];
    Anthony.Location=A;
    return 0;
}

---

I like the approach you are taking to this project.. but at the same time I see some basic areas of improvement.. for starters:

Code:

---

class Space
{
public:

private:
string Description;
};

---

There is nothing in the public area of this class.. which isn't wrong.. but a class isn't a class without some sort of function.

Code:

---

class Player
{
public:
Space **Location;
private:

};

---

Similar problem with the Player class.. location (although i'm not sure if it's declared correctly) I think should appear in the private area of the class.


General Class Format:

Public: will contain class member functions

Private: will contain class variables.. which can only be accessed by class member functions or friend functions


I like seeing the use of the double pointer to reference the 2 dimensional array.. but that's a technique I haven't specifically used myself.. so I cannot make a judgement right off hand as to its correctness.

I would like to see more code if you don't mind. :)

Bah, beaten by microseconds...

Hello, Thank you for the fast replies. Let me try to explain what I was tring to do.
I put the:

Code:

---

Space **Location

---

Thinking I can use it to Point to an Multi-dimensional array. Then I can access the Array though the Pointer to pointer Location.

Code:

---

Space (*Location)[10];

---

That looks good, but I didn't want to specify how much the array will be. Since the Rooms will change for each Level.
I wanted to assign more then 10 to some rooms I make.
The Space class I wanted to hold information liike:
Description of each spot the player moves to within the room Muti-dimensional array. And Location will keep track of his concordinates. and I can manipulate Location for Methods such as Move and stuff Ill add later.
Why did I get the Debug Assert Error? and Is there a way I can Make it where I can Use A Location Pointer Without specifying the size of the array it takes? Like I was tring to do. Make it where location can point to a room made of spaces of any size. And Manipulate Location like a multi-dimensional array? Im a beginner, so I have hard time understanding code. I actually been tring to teach myself programming off and on for 4 years but Im not very good at it. Thanks for your patience and Responce :)
The Brain, Thanks for your feedback and help on how to lay out my class. I actually left the methods out on purpose, until I fixed my error. I just started to make the project so I dont have more then this. Sorry.
Thanks

>but I didn't want to specify how much the array will be
You have no choice if you want to point to a multidimensional array. The alternative is to dynamically allocate your own simulated array, or use a standard container class.

Quote:

---

but I didn't want to specify how much the array will be.

---

Not a problem.. if you don't want to declare a static array with a fixed size.. just use a dynamic two dimensional array.

Just keep in mind: int array[variable]; //is illegal in c++


Legal: int *array = new array[variable];

I have never seen posts come up this fast.

hehe, Yea the posting is coming up pretty fast. I'm lets say not the most advance programmer in the world. Pointers and dynamic memory and stuff confuses me. And Sometimes I ask a lot of questions, and start to annoy people, but I hope that dont happen here. So You guys are saying there is no way for me to make a pointer point to an multi-dimensional array, without defining a size? :( And I have to use A Dynamic Array to acommplish this? I don't know if Im advance enough to do such a thing. I can do basic dynamic stuff. I understand what you posted brain. But why cant I point to a multi-dimensional array with a pointer without definfing a size? You can do that with Pointers which arent pointed to multi-dimensional arrays? Right? I ask a lot of questions cause its hard for me to learn without knowing everything. If I were to make it a dynamic array. like

Code:

---

Anthony.Location= new Space[10];
for( int i=0;i<10;i++){
Anthony.Location[i]=new Space[5];
}

---

?
ok I have no clue what Im doing LOL. Sorry

sorry I meant

Code:

---

Anthony.Location= new Space[10];
for( int i=0;i<5;i++){ // 5 not 10
Anthony.Location[i]=new Space[5];
}

---

Close!

Code:

---

Anthony.Location = new Space*[10];
for( int i=0;i<10;i++){
    Anthony.Location[i]=new Space[5];
}

---

DAHHHH... Lol Salem, I found that out actually before I viewed the email saying I got a reply from the Site. You beat me hehe. I was tinkering with the Code and I actually Got the same solution as you. Thanks for the solution :D
Here is my new Workable Game thus far...

Code:

---

#include <iostream>
#include <string>
using namespace std;
class Space
{
public:
void SetDescription(string);
string GetDescription();
private:
string Description;
};
string Space::GetDescription(){
return Description;
}
void Space::SetDescription(string Description){
this->Description=Description;
}
class Player
{
public:
Space **Location;
private:

};


int main(){
Player Anthony;
Anthony.Location= new Space*[10];
for( int i=0;i<5;i++){ // 5 not 10
Anthony.Location[i]=new Space[5];
}
Anthony.Location[1][3].SetDescription(" You Found A CREEPY STAIRWAY");
cout<<Anthony.Location[1][3].GetDescription();


system("PAUSE");
return 0;
}

---

Thanks Everyone. I hate to leave you all. You been great. Im going to be posting a lot on here now that Im here, Cause Im sure Ill make millions more mistakes. This forume is very Helpful. THank you :D Kinda sad My problem was solved now Sniffle. LOL :D

Wait I keep forgetting things. I need to review more before I post LOl.

Code:

---

Anthony.Location[1][3].SetDescription(" You Found A CREEPY STAIRWAY");
cout<<Anthony.Location[1][3].GetDescription();

delete[] Anthony.location;

Anthony.location=NULL;

---

is that right?

I mean

Code:

---

delete[] Anthony.Location;

Anthony.Location=NULL; // forgot to cap the L on location.

---

Ok Im sorry. Im posting too Much. Im going to stop LOL byebye all

Try it out. Looks good.


Note, you have only allocated memory for 5 of the possible 10 elements in Anthony.Location. If you try doing this:

Anthony.Location[5][1].setDescpription("BOO!");

your program may well behave erratically or, if you're lucky, crash. To fix this potential problem, look more closely at Salem's code.

OHHHHHHHHHHHHHHH. I SEE THE ERROR NOW :)) LOL I accidently put the loop for 5 not 10
THANKS :D

I believe it should be like this:

Code:

---

Anthony.Location = new Space*[10];
for( int i=0;i<10;i++){
    Anthony.Location[i]=new Space[5];
}
//...
for( int i=0;i<10;i++){
delete [] Anthony.Location[i];
}
delete [] Anthony.Location;

---

Also, your class design isn't all that great. Any data in a class should generally be declared with private scope, and then you should declare a constructor and destructor to allocate/deallocate memory:

Code:

---

class Player
{
public:
Player(int r=10,int c=5);
~Player();
private:
Space** Location;
int rows,cols;
};
Player::Player(int r, int c)
{
  rows=r;
  cols=c;
  Anthony.Location = new Space*[r];
  for( int i=0;i<r;i++){
      Anthony.Location[i]=new Space[c];
  }

}
Player::~Player()
{
  for(int i=0;i<rows;i++){
    delete [] Anthony.Location[i];
  }
  delete [] Anthony.Location[i];
}

---

You should probably review a tutorial on classes before you move on :)

Edit: Whoops missed the [] in the second part

:D I Know my Class isn't that Great. Im Just Tring to get the Parts working before I start organizing it better. But then again Im just a beginner. So It wasnt going to get much more better then it was without help LOL. :D Thanks for the Help. The Correct way to Delete really Helped. Also I would change your code a tad. So that Space handles all the Memory Allocations and stuff. And Addings new levels. I liked the new additions with the constructors. I need to learn more on classes I agree. However I think Coding and learning as I go is helping me a whole lot. Im not a real good learner when it comes to reading. And then It is hard for me to remember the things I learn on my way LOL. Thanks for all the good advice. :D