[RESOLVED] problems on resize an array:(

i have 1 class with several class's and 1 struture:

Code:

---

struct Images
{   
    HBITMAP ImageImage;
    BITMAP Imagebm;
    HDC ImagehdcMem;
    HBITMAP ImageMaskImage;
    BITMAP ImageMaskbm;
    HDC ImageMaskhdcMem;
};

//the subclass
class subimages
{
    public: int ActualSubimage;
    public: int TotalSubimages;
    public: struct Images *SubImages;
....................................
//how i use it:
..................
sprite2 a,b,c;
a.Visible =true;
a.Direction=Left;
a.Images.Image1.Stop.SubImages=(struct Images)malloc(1 * sizeof(struct Images));
....................

---

but i get these error:
"--------------------Configuration: Sprite2 - Win32 Debug--------------------
Compiling...
Test Sprite2.cpp
C:\Users\Joaquim\Documents\Visual C 98\Sprite2\Test Sprite2.cpp(23) : error C2440: 'type cast' : cannot convert from 'void *' to 'struct Images'
No constructor could take the source type, or constructor overload resolution was ambiguous
Error executing cl.exe.

Sprite2.exe - 1 error(s), 0 warning(s)"
i try search more code, but i get more errors:(
can anyone advice me?

Why are you using malloc instead of new?

Why are you multiplying by 1?

Most importantly, malloc returns a pointer. Why are you casting it to a struct?

Quote:

---

Originally Posted by GCDEF

Why are you using malloc instead of new?

Why are you multiplying by 1?

Most importantly, malloc returns a pointer. Why are you casting it to a struct?

---

you have right the 'new' is more easy to use, but i get errors too:(
by 1, because, in these test, i only need 1 subimage

Code:

---

a.Images.Image1.Stop.SubImages= new Images[1];

---

i execute the program but the windows give me an errror and then close it(sorry not a normal error message). and in subclass i have 1 pointer like you see that code.
i'm trying but seems that is more complicaded with struct that normal types:(

What is a.Images.Image1.Stop.SubImages?
What's the point of creating an array of size 1?

Your code seems pretty confused.

Quote:

---

Originally Posted by GCDEF

What is a.Images.Image1.Stop.SubImages?
What's the point of creating an array of size 1?

Your code seems pretty confused.

---

sorry about that.. i will try do my best(i'm portuguese);)
i'm doing a class Sprite these class have several subclass's for be more easy to use;)
sprite a;
a.Images.Image1.Stop.SubImages....;
the SubImages word is 1 variable from a struture:

Code:

---

struct Images
{   
    HBITMAP ImageImage;
    BITMAP Imagebm;
    HDC ImagehdcMem;
    HBITMAP ImageMaskImage;
    BITMAP ImageMaskbm;
    HDC ImageMaskhdcMem;
};

---

like you see the SubImages is a Images type\structure. but i need do a dinamic array, because not all animations have 100 subimages. and a good programmer don't use so many memory, if he don't need;)
i try use the 'new' keyword(from C++) and malloc() function(from C), but without sucess. maybe because i'm using a struture.
i can share all the code;)
please tell me something for i start see\read. and loking for some code it's very complicated, because theres several C\C++ versions and not all code works on Visual C++ 6(i have the 2010 too).
sorry if my english is bad, but i'm trying

Quote:

---

i execute the program but the windows give me an errror and then close it(sorry not a normal error message).

---

What error? What debugging of the program have you done to find out what is the cause of the error? Which line in the program is giving the error? If you want our help you'll need to provide more info than just 'gives an error' and also you'll need to post the code - not just a few lines - so that we can look at it (properly formatted with code tags please).

Quote:

---

Originally Posted by Cambalinho

sorry about that.. i will try do my best(i'm portuguese);)
i'm doing a class Sprite these class have several subclass's for be more easy to use;)
sprite a;
a.Images.Image1.Stop.SubImages....;
the SubImages word is 1 variable from a struture:

Code:

---

struct Images
{   
    HBITMAP ImageImage;
    BITMAP Imagebm;
    HDC ImagehdcMem;
    HBITMAP ImageMaskImage;
    BITMAP ImageMaskbm;
    HDC ImageMaskhdcMem;
};

---

like you see the SubImages is a Images type\structure. but i need do a dinamic array, because not all animations have 100 subimages. and a good programmer don't use so many memory, if he don't need;)
i try use the 'new' keyword(from C++) and malloc() function(from C), but without sucess. maybe because i'm using a struture.
i can share all the code;)
please tell me something for i start see\read. and loking for some code it's very complicated, because theres several C\C++ versions and not all code works on Visual C++ 6(i have the 2010 too).
sorry if my english is bad, but i'm trying

---

Your English is fine. I'd get away from VC 6 and focus on 2010. Then you can take advantage of STL and dynamic arrays such as vector. If you're using MFC, even in VC 6 you can use their dynamic arrays such as CPtrArray or CObArray.

FWIW, it's not necessarily true that you don't use more memory than you need. An fixed array of size 100 that just stores pointers, even if you don't use them all, isn't really an excessive use of memory.

Quote:

---

Originally Posted by Cambalinho

i have 1 class with several class's and 1 struture:

Code:

---

struct Images
{   
    HBITMAP ImageImage;
    BITMAP Imagebm;
    HDC ImagehdcMem;
    HBITMAP ImageMaskImage;
    BITMAP ImageMaskbm;
    HDC ImageMaskhdcMem;
};

//the subclass
class subimages
{
    public: int ActualSubimage;
    public: int TotalSubimages;
    public: struct Images *SubImages;
....................................
//how i use it:
..................
sprite2 a,b,c;
a.Visible =true;
a.Direction=Left;
a.Images.Image1.Stop.SubImages=(struct Images)malloc(1 * sizeof(struct Images));
....................

---

but i get these error:
"--------------------Configuration: Sprite2 - Win32 Debug--------------------
Compiling...
Test Sprite2.cpp
C:\Users\Joaquim\Documents\Visual C 98\Sprite2\Test Sprite2.cpp(23) : error C2440: 'type cast' : cannot convert from 'void *' to 'struct Images'
No constructor could take the source type, or constructor overload resolution was ambiguous
Error executing cl.exe.

Sprite2.exe - 1 error(s), 0 warning(s)"
i try search more code, but i get more errors:(
can anyone advice me?

---

The biggest advice is to improve your C++ skills. Regardless of what you want to do, you can't throw together a program in C++ that requires knowledge beyond the basics and have it work.

First, I would suggest renaming your struct. You called it "Images" when it really can be only one "Image".

Second:

Code:

---

#include <vector>
#include <memory>

struct ImageInfo
{   
    HBITMAP ImageImage;
    BITMAP Imagebm;
    HDC ImagehdcMem;
    HBITMAP ImageMaskImage;
    BITMAP ImageMaskbm;
    HDC ImageMaskhdcMem;
};

typedef std::shared_ptr<ImageInfo>  ImageInfoPtr;
typedef std::vector<ImageInfoPtr> ImageInfoPtrVect;

---

So you now have two things here:

1) You have a smart pointer of ImageInfo called ImageInfoPtr.
2) You can now store multiple ImageInfoPtr into a vector of type ImageInfoPtrVect. This will be the dynamic array.

Code:

---

ImageInfoPtrVect imVector;
ImageInfoPtr imPtr = ImageInfoPtr(new ImageInfo);
//..now assume imPtr has been set up with its information
//... add it to our vector
imVector.push_back( imPtr );

---

So what does this give you?

1) You now have a dynamic array of Images
2) The memory management is controlled by the shared_ptr. When the last reference is gone, the memory manager takes care of deleting the memory.

For 2), you may want to use unique_ptr instead of shared_ptr for your purposes. But regardless, this is how an experienced C++ programmer would approach this issue -- that is to use the standard library, containers, and smart pointers to simplify the work. Approaching the problem as if it's low-level 'C' programming as you did in your attempts is not the way to go about this.

Regards,

Paul McKenzie

Quote:

---

Originally Posted by Paul McKenzie

The biggest advice is to improve your C++ skills. Regardless of what you want to do, you can't throw together a program in C++ that requires knowledge beyond the basics and have it work.

First, I would suggest renaming your struct. You called it "Images" when it really can be only one "Image".

Second:

Code:

---

#include <vector>
#include <memory>

struct ImageInfo
{   
    HBITMAP ImageImage;
    BITMAP Imagebm;
    HDC ImagehdcMem;
    HBITMAP ImageMaskImage;
    BITMAP ImageMaskbm;
    HDC ImageMaskhdcMem;
};

typedef std::shared_ptr<ImageInfo>  ImageInfoPtr;
typedef std::vector<ImageInfoPtr> ImageInfoPtrVect;

---

So you now have two things here:

1) You have a smart pointer of ImageInfo called ImageInfoPtr.
2) You can now store multiple ImageInfoPtr into a vector of type ImageInfoPtrVect. This will be the dynamic array.

Code:

---

ImageInfoPtrVect imVector;
ImageInfoPtr imPtr = ImageInfoPtr(new ImageInfo);
//..now assume imPtr has been set up with its information
//... add it to our vector
imVector.push_back( imPtr );

---

So what does this give you?

1) You now have a dynamic array of Images
2) The memory management is controlled by the shared_ptr. When the last reference is gone, the memory manager takes care of deleting the memory.

For 2), you may want to use unique_ptr instead of shared_ptr for your purposes. But regardless, this is how an experienced C++ programmer would approach this issue -- that is to use the standard library, containers, and smart pointers to simplify the work. Approaching the problem as if it's low-level 'C' programming as you did in your attempts is not the way to go about this.

Regards,

Paul McKenzie

---

sorry i'm learning C by me... then i will learn C++;)
sorry can you give me a nice link about these for i understand more?;)
thanks for all

Quote:

---

Originally Posted by Cambalinho

sorry i'm learning C by me...

---

Then you should be using a 'C' compiler only. You are mistakingly using a C++ compiler, and using a C++ compiler that uses C++ rules to learn 'C' programming is totally wrong.

Quote:

---

Sprite2.cpp
//...
class subimages

---

This is in your first post. This means that the program is a C++ program. If you're using Visual C++, and you haven't changed any of the IDE options, any file with a .cpp extension is a C++ program. In addition, there is no such thing as a class in the 'C' language.

Either rename your file with a .C extension, or force Visual Studio to apply the rules of 'C' to your program.

Quote:

---

then i will learn C++;)

---

If your goal is to learn C++ programming, learning 'C' is not a requirement. Either learn C, or learn C++.

http://www.parashift.com/c++-faq/don...n-c-first.html

Regards,

Paul McKenzie

You are not casting the return value from malloc to the correct type:

Code:

---

a.Images.Image1.Stop.SubImages=(struct Images *)malloc(1 * sizeof(struct Images));

---

Quote:

---

Originally Posted by Paul McKenzie

Then you should be using a 'C' compiler only. You are mistakingly using a C++ compiler, and using a C++ compiler that uses C++ rules to learn 'C' programming is totally wrong.
This is in your first post. This means that the program is a C++ program. If you're using Visual C++, and you haven't changed any of the IDE options, any file with a .cpp extension is a C++ program. In addition, there is no such thing as a class in the 'C' language.

Either rename your file with a .C extension, or force Visual Studio to apply the rules of 'C' to your program.
If your goal is to learn C++ programming, learning 'C' is not a requirement. Either learn C, or learn C++.

http://www.parashift.com/c++-faq/don...n-c-first.html

Regards,

Paul McKenzie

---

thanks i didn't knew;)
more quickly i start for C++;)

Quote:

---

Originally Posted by Philip Nicoletti

You are not casting the return value from malloc to the correct type:

Code:

---

a.Images.Image1.Stop.SubImages=(struct Images *)malloc(1 * sizeof(struct Images));

---

---

sorry i'm trying do these thing, but now i have a head pain:(
and i, always, get errors:(

Quote:

---

Originally Posted by Cambalinho

sorry i'm trying do these thing, but now i have a head pain:(
and i, always, get errors:(

---

That is because handling dynamic memory requires that you know what you're doing. You can't just hope to get it right, you must know that it's right. You must start out with something very simple, and know what you're doing before going further. In addition, where are you freeing the memory? You have to do that also, or else it's a memory leak.

However, if you went straight to C++, you have very little, if any contact with malloc(). Look at the code I wrote -- you don't see one call to malloc() because it's not needed. I have a dynamic array, and I can now go forward with the rest of the program, while you're still having problems. So what is your goal, to write a program that processes images, or fight with malloc()?

Regards,

Paul McKenzie

Quote:

---

Originally Posted by Paul McKenzie

That is because handling dynamic memory requires that you know what you're doing. You can't just hope to get it right, you must know that it's right. You must start out with something very simple, and know what you're doing before going further. In addition, where are you freeing the memory? You have to do that also, or else it's a memory leak.

However, if you went straight to C++, you have very little, if any contact with malloc(). Look at the code I wrote -- you don't see one call to malloc() because it's not needed. I have a dynamic array, and I can now go forward with the rest of the program, while you're still having problems. So what is your goal, to write a program that processes images, or fight with malloc()?

Regards,

Paul McKenzie

---

sorry to all.. finally i resolve it.. with very hard work and head pain(but works);)

how i did:

1 - i must create a pointer in my class with my struture name(my sample is these way, but we can use any type and class's elements):

Code:

---

public: ImageInfo *SubImages;

---

ImageInfo is my struture name.

2 - now we must put that pointer to null:

Code:

---

classname class1;
class1.SubImages=NULL;

---

3 - now we can use realloc() for resize the array(i think that malloc() can be used too;)):

Code:

---

class1.SubImages = (ImageInfo*) realloc (class1.SubImages, 1 * sizeof(ImageInfo));

---

the '1' is for tell you that i only need with 1 element on array;)

4 - after we don't need. we must delete it.
(sorry can anyone tell me how?)

5 - if you execute the program and the windows gives you an error and close the program, see if you have another variable with that pointer. the pointer is declared but without size(elements), then it can't be used normaly, only after give it elements(i have tested without know it);)

anotherthing: i'm trying do a nice function for resize arrays, but i get some errors:

Code:

---

int ReDim(void *ag,size_t i)
{
        (typeid(ag).name()*) realloc (ag, i * sizeof(typeid(ag).name()));
        return 0;
}

---

error message:
"--------------------Configuration: Sprite2 - Win32 Debug--------------------
Compiling...
Test Sprite2.cpp
C:\Users\Joaquim\Documents\Visual C 98\Sprite2\Test Sprite2.cpp(12) : error C2059: syntax error : ')'
Error executing cl.exe.

Sprite2.exe - 1 error(s), 0 warning(s)"
strange error... i have 14 parenteses... they are multiply of 2, then why the error?
and here how use it:

Code:

---

ReDim(&class1.SubImages,1);

---

Code:

---

int ReDim(void *ag,size_t i)
{
        (typeid(ag).name()*) realloc (ag, i * sizeof(typeid(ag).name()));
        return 0;
}

---

Whatever you thought this code was going to accomplish, it doesn't! :confused::thumbd:

realloc returns a pointer to the new memory and needs to be assigned. ag is a pointer to void passed by value so that even if ag is assigned to the return value of realloc, the new value won't get returned to the caller. ag either needs to be passed as a pointer to a pointer or (better) as a reference to a pointer. typeid(..).name() returns a const char * string so sizeof will always give the wrong value (and in any case doesn't provide what you think it provides!).

As Paul already stated, why are you trying to incorrectly use the 'c' method of memory allocation when there are so much better ways of doing this in c++???? If you insist on using malloc/realloc/free then you need a good understanding of how this all hangs together and how pointers work and how to pass values back from functions etc etc etc.

Quote:

---

Originally Posted by Cambalinho

sorry to all.. finally i resolve it.. with very hard work and head pain(but works);)

---

There is one thing you need to realize:

When you do something incorrect when it comes to memory handling, just because the program "works" doesn't mean the program is correct. In C (or C++), if you make a mistake, there may be no indication that something is wrong, until you run the program on another computer, or the program may run some time and crash another time, etc.

That's why your attempt at trying to manage your own memory is flawed. I have never seen any code like this to allocate memory, and I've been doing C and C++ for 25 years now:

Code:

---

int ReDim(void *ag,size_t i)
{
  (typeid(ag).name()*) realloc (ag, i * sizeof(typeid(ag).name()));
  return 0;
}

---

Now, if I've never seen anything like this before from a beginner, then you know something just isn't right.

First, there is no such thing as typeid in the 'C' language. So why are you using it?

Second, even if you were to do something like this in C++, you would use a template:

Code:

---

template <typename T>
T* ReDim(void *ag,size_t i)
{
  return (T*) realloc (ag, i * sizeof(T));
}

---

Third, why do this when again, you have std::vector? All you need to do is call the resize() method to resize the vector.

Quote:

---

4 - after we don't need. we must delete it.
(sorry can anyone tell me how?)

---

See what I mean when I stated you must know what you're doing? If you're asking us "where to delete the memory", then frankly, you're not ready for this type of programming where you're handling dynamically allocated memory. But again, there is no need to do this type of programming at all for your purposes.

Quote:

---

Sprite2.exe - 1 error(s), 0 warning(s)"
strange error... i have 14 parenteses... they are multiply of 2, then why the error?
and here how use it:

---

Your program is written poorly from the beginning. Trying to answer your question concerning a syntax error will just encourage you to do more of the same bad programming.

Regards,

Paul McKenzie

Quote:

---

Originally Posted by Paul McKenzie

There is one thing you need to realize:

When you do something incorrect when it comes to memory handling, just because the program "works" doesn't mean the program is correct. In C (or C++), if you make a mistake, there may be no indication that something is wrong, until you run the program on another computer, or the program may run some time and crash another time, etc.

That's why your attempt at trying to manage your own memory is flawed. I have never seen any code like this to allocate memory, and I've been doing C and C++ for 25 years now:

Code:

---

int ReDim(void *ag,size_t i)
{
  (typeid(ag).name()*) realloc (ag, i * sizeof(typeid(ag).name()));
  return 0;
}

---

Now, if I've never seen anything like this before from a beginner, then you know something just isn't right.

First, there is no such thing as typeid in the 'C' language. So why are you using it?

Second, even if you were to do something like this in C++, you would use a template:

Code:

---

template <typename T>
T* ReDim(void *ag,size_t i)
{
  return (T*) realloc (ag, i * sizeof(T));
}

---

Third, why do this when again, you have std::vector? All you need to do is call the resize() method to resize the vector.
See what I mean when I stated you must know what you're doing? If you're asking us "where to delete the memory", then frankly, you're not ready for this type of programming where you're handling dynamically allocated memory. But again, there is no need to do this type of programming at all for your purposes.
Your program is written poorly from the beginning. Trying to answer your question concerning a syntax error will just encourage you to do more of the same bad programming.

Regards,

Paul McKenzie

---

thanks to all