|
What kind of array are you using? Could you please post array declaration?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
|
The size of such array is
int iSize = sizeof(store);
The number of elements of such array is
int iCount = sizeof(store)/sizeof(store[0]);
or, more concisely, 100 .
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
Thanks for reply but it's not working.
CString store[100];
CString File;
and int cou=0;
store[cou]=File.
File name added at the run time.Plz help me
|
|
|
|
|
What does it mean 'it's not working?' in such context?
What are you trying to do?
What happens instead?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
store[cou]=File;
int iSize=sizeof(store);
AfxMessageBox(iSize);
Then i am geting Debug Assertion Fail Line number:163.
|
|
|
|
|
On what line does the code assert?
BTW your array is fixed-sized to 100 elements, regardless if you assign or not any of them.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
Thank Now it is working.Your code is good.I make a mistake.SO thanks again.Ome more question how can i use dynamic array.Plz help me
|
|
|
|
|
If you need an array that grows dynamically then have a look at std::vector .
MFC has the CArray container but it's a crap (please don't tell this to Rajesh ).
very basic (and naive) vector usage sample follows:
#include <iostream>
#include <string>
#include <vector>
using namespace std;
void main()
{
vector < string > v;
v.push_back(string("hi,"));
v.push_back(string("how"));
v.push_back(string("do you do?"));
cout << "vector size = " << v.size() << endl;
for (int i=0; i<v.size(); i++)
{
cout << v[i] << " ";
}
cout << endl;
}
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
Thanks for help.Every reply boost me..
|
|
|
|
|
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
|
|
|
|
|
In one of my projects I have an array of pointers to Tile 's (a class of my own) within a Block class. Upon calling the constructor for the Block class I assign the pointer to each Tile in the array to the address of a Tile created on the heap using the new operator like so;
Block::Block()
{
while(i=0; i < 20; i++)
{
Array_of_pointers_to_Tiles[i] = new Tile;
}
}
I then call the delete operator in the destructor like so;
Block::~Block()
{
while(i=0; i < 20; i++)
{
delete Array_of_pointers_to_Tiles[i];
Array_of_pointers_to_Tiles[i] = NULL;
}
}
This code does not compile.
According to this resource[^] I am to allocate the array like so;
int* a = NULL;
int n;
cin >> n;
a = new int[n];
for (int i=0; i<n; i++) {
a[i] = 0;
}
. . .
delete [] a;
a = NULL;
and to free the memory allocated to the array;
delete [] a;
a = NULL;
However this code doesn't compile either!
What is the correct way?!?
modified on Monday, September 29, 2008 1:44 AM
|
|
|
|
|
Can you tell what is the compiler error?
Saurabh
|
|
|
|
|
As soon as I get home, yes
I'm at work
|
|
|
|
|
Okay, so it turns out that I was accessing each array element using the points-to operator instead of the dot-operator :P
You can't use the points-to operator in this situation because when you think about it, it doesn't make any sense to :P
EDIT: When running in debug mode I get a debug assertion failure. Attempting to debug produces this:
"0 > 8828 Main Thread Main Thread Tile::`vector deleting destructor' Normal 0"
on the line delete [] p_TileArray;
What's going on?
modified on Tuesday, September 30, 2008 3:08 AM
|
|
|
|
|
Unless we see how you defined the array (from your Block class definition), we're not going to be able to help...
Iain.
|
|
|
|
|
In Block.h
class Block
{
public:
Block(void);
Block(int itsShape, int itsColour);
~Block(void);
bool isGrounded(void);
void MoveLeft();
void MoveRight();
void MoveDown();
void Rotate();
void Render();
private:
int Shape;
int Colour;
bool Grounded;
Tile* p_TileArray;
};
in Block.cpp
#include "Block.h"
Block::Block(void)
{
Grounded = false;
Shape = (rand() % 7);
Colour = (rand() % 6);
p_TileArray = NULL;
p_TileArray = new Tile[4];
p_TileArray[0].SetPos(498.0, 82.0);
p_TileArray[1].SetPos(530.0, 82.0);
p_TileArray[2].SetPos(498.0, 114.0);
p_TileArray[3].SetPos(530.0, 114.0);
}
Block::~Block(void)
{
if (p_TileArray)
{
delete [] p_TileArray;
p_TileArray = NULL;
}
}
bool Block::isGrounded(void)
{
return Grounded;
}
void Block::MoveLeft()
{
if(Grounded == false)
{
for(int i = 0; i < (sizeof(p_TileArray) / sizeof(p_TileArray[0])); i++)
{
p_TileArray[i].MoveLeft();
}
}
}
void Block::MoveRight()
{
if(Grounded == false)
{
for(int i = 0; i < (sizeof(p_TileArray) / sizeof(p_TileArray[0])); i++)
{
p_TileArray[i].MoveRight();
}
}
}
void Block::MoveDown()
{
if(Grounded == false)
{
for(int i = 0; i < (sizeof(p_TileArray) / sizeof(p_TileArray[0])); i++)
{
p_TileArray[i].MoveDown();
}
}
}
void Block::Rotate()
{
}
void Block::Render()
{
for(int i = 0; i < (sizeof(p_TileArray) / sizeof(p_TileArray[0])); i++)
{
p_TileArray[i].Render();
}
}
|
|
|
|
|
On the code above, I'm quite surprised at the delete [] failing, unless there is a problem inside the destructor for Tile.
Have you tried making a test app, and tried Tile as a very simple class (ie, just an int ), and implicit constructor / destructor?
Also put a breakpoint on your allocation and deallocation part, and make sure you haven't messed up the address of p_TileArray.
Lastly, I can see one other bug, which is in place many times.
for(int i = 0; i < (sizeof(p_TileArray) / sizeof(p_TileArray[0])); i++)
As m_pTileArray is a pointer, sizeof(p_TileArray) will be 4 on a 32 bit system, and 8 on a 64 one. I'm assuming sizeof (Tile) is larger, so your loops will never work. When you weren't dynamically allocating Tiles, and had Tile p_TileArray[4]; (I'm guessing), then the sizeof trick would work nicely.
You;'ll need a separate member variable to tell the loops how many you have.
eg:
p_TileArray = NULL;
n_TileArray = 4;
p_TileArray = new Tile[n_TileArray];
You may also want to use array structures to hold the tiles, which will clear things up.
In block.h
CArray<Tile, Tile &> m_Tiles;
In block.cpp
constructor
m_Tiles.SetSize (4);
m_Tiles [0].Set....
...
void Block::Render()
{
for(int i = 0; i < m_Tiles.GetSize (); i++)
{
m_Tiles[i].Render();
}
}
If you prefer, you could use std::vector instead. Either choice frees you from needing to delete the dynamic "array", and may help you.
Good luck,
Iain.
|
|
|
|
|
thanks for pointing that out
I would use a vector but it seems overkill as there's only 4 elements in the array. The reason I'm dynamically allocating them is because as far as I know, it's not possible to allocate four tile's to each block before compile time. It just doesn't work.
I considered that maybe it was actually a problem with the Tile's destructor, but couldn't spot anything out of place. The following is the constructor and destructor for the Tile class;
Tile::Tile(void)
{
*p_iNumTiles++;
left = 0;
top = 0;
depth = 0;
sizex = 0;
sizey = 0;
sizez = 0;
}
Tile::~Tile(void)
{
*p_iNumTiles--;
}
|
|
|
|
|
Sauce! wrote: as far as I know, it's not possible to allocate four tile's to each block before compile time
I don't see why not - unless the Tile class requires knowledge of the Block class, simply declare it earlier, then make a static array. 99% of your problems go away. You could also use a #define NUMTILESPERCLOCK 4 rather hard wiring 4, and use the define in your loops.
The bit that worries me in the code you posted is the
Sauce! wrote:
*p_iNumTiles++;
*p_iNumTiles--;
If this is a pointer to some ref counting integer, where is it assigned? If it is a global integer, why are you using pointers? Maybe it's valid during the constructor stage, but not during the destructor, in which case bad things happen - as you see...
Without knowing more of the why / how of p_iNumTiles I run out of steam. Can you get rid of it, and see if all gets better?
Iain.
|
|
|
|
|
Oh dear, I am so silly :P
That ought to teach me not to reuse old code that has never been tested.
It was simply a pointer to a static int (that was supposed to be) declared in the tile class. Stupid me, put it outside of the tile class for some unknown reason, which made it inaccessible to the Tile class.
Unfortunately though, removing it doesn't fix the problem
I will try what you said and get back to you, though for the mean time I have another question: How do you use a static variable to count the number of classes you have? I can do everything but initialise the variable - C++ simply doesn't let you initialise non const member variables within a class, so where am i supposed to initialise the count to 0? Take the following code as an example;
class theClass
{
public:
theClass(void);
~theClass(void);
private:
static int theCount = 0;
};
theClass::theClass()
{
theCount++
}
theClass::~theClass()
{
theCount--
}
|
|
|
|
|
Header:
class CMyClass
{
public:
CMyClass ();
~CMyClass ();
protected:
static int g_MyCounter;
};
cpp file:
int CMyClass::g_MyCounter = 0;
CMyClass::CMyClass ()
{
g_MyCounter++;
}
CMyClass::~CMyClass ();
{
ASSERT(g_MyCounter);
g_MyCounter--;
}
Given that you have a fixed number per block, I really can't see any point in you doing this for this application though... That static member variable is shared between all instances of CMyClass. I use this technique a lot for registered messages.
eg:
UINT CMyTopSecretClass::m_wm_SomeMessage = ::RegisterWindowMessage ("CMyTopSecretClass::m_wm_SomeMessage");
I hope this helps,
Iain.
|
|
|
|
|
Thanks, I thought that's how you were meant to do it, but it just doesn't feel "right" because you're assigning a value to something outside of a function... so when does that value get assigned? During compile-time? At run-time?
I've done what you said and simply created an array of Tile's with 4 elements... Now i get the error
"Error 7 error C2148: total size of array must not exceed 0x7fffffff bytes c:\users\bryce\documents\visual studio 2008\projects\...\...\block.h 29"
My tile class certainly isn't that large... (half a terabyte if my calculations are correct!)
If I can't figure that out then I'll involve vectors >_>
EDIT: it may interest you to know that I also get the error "Error 2 error C2079: 'Block::TileArray' uses undefined class 'Tile' c:\users\bryce\documents\visual studio 2008\projects\...\...\block.h 29"
This is the problem I was coming across earlier and is the reason I thought it wasn't possible to do this. I have a forward declaration for the Block class right before my Tile class, but there is still no way for it to know it's definition. How can I overcome this?
modified on Tuesday, September 30, 2008 11:09 AM
|
|
|
|
|
|
It should then, be as simple as putting #include "Tile.h" at the top of Block.h but this still doesn't quite do it Those two errors remain.
|
|
|
|