array declaration question

[%chess%]

my.cpp file:

#define size 55


int array1[size];
int *array2[size];

size may vary.

if i add these to my.h file as:

int array1[];
int *array2[];

i get error: an illegal zero-sized array.

how do i handle this?.

[gstercken]

how do i handle this?.

Like this, for example:

int*  array1;
int** array2;

But since you are using C++: Why bother about C-style arrays at all, and not std::vector instead?

Besides that: What's your intention behind declaring a variable in a header file? That's usually not a good idea.

[Paul McKenzie]

If your goal is to have a resizable array, use the std::vector class that has been discussed here many times.

Regards,

Paul McKenzie

[%chess%]

int *databuf[arraysize];

for (int i = 0; i < 10; i++)
databuf[i] = new int[sizeofdata];

do i do the above with vectors?.

[jlou]

You can do the equivalent by constructing a vector of vectors of ints using the constructors that take the initial size of the vector:

std::vector<std::vector<int> > databuf(arraysize, std::vector<int>(sizeofdata));

You can also use typedefs to make the code smaller if the look of it bothers you.

[%chess%]

std::vector<std::vector<int> > databuf(m_arraysize, std::vector<int>(m_sizeofdata));

How do i access this globally within an object from different functions?
i was getting an error when added it to public member of
CMy class. need to push to its stack area from one function and
pop from its stack area from another function.

unknown m_arraysize.it needs to know m_arraysize?. maybe i cam confused.
could you illustrate more?.

[jlou]

As part of a class, you declare it in the class and initialize it in the constructor(s)' initializer list(s):

class Example
{
public:
  Example(int arraysize, int sizeofdata) : databuf(arraysize, std::vector<int>(sizeofdata))
  { }

  int getArraySize() const { return databuf.size(); }
  int getSizeOfData(int index = 0) const { return databuf.at(index).size(); }

private:
  std::vector<std::vector<int> > databuf;
}

If you are still unsure, you might want to post more of your code so we know what exactly you are having trouble with. There are more ways to initialize your vectors than the way I used above, but hopefully you will be able to figure out how to get the sizes to the constructor on your own.

[%chess%]

sorry, One last thing since i am starting to look at
vectors more seriously than just a c++ extra thing.

How do i pass each databuf buffer to PutDataInBuffer function
to put data into it?. that was my intention. to allocate space
and pass it on.

for (int i = 0; i < size; i++)
{
	BOOL (PutDataInBuffer(dataBuffers[i], Status))
	{
		//
	}
}

[%chess%]

I guess this what should pass databuf[idx].at(idx)....???
should work...

[Andreas Masur]

int *databuf[arraysize];

for (int i = 0; i < 10; i++)
databuf[i] = new int[sizeofdata];

do i do the above with vectors?.

Take a look at the following introduction to the 'vector' class...