passing refs for 2D arrays

[jxxnorth]

What is the correct way to pass a 2d array by ref to a function. This is what I've tried...

void foo (int** array); // or void foo (int*[] array); ??

int main(){
int array[10][10];

foo(array);
}

void foo(int** array){
array[0][0] = 1;
}

 

[Leibnitz]

you can do it like this:

#define _MAXSIZE_  10

void foo (int array[][_MAXSIZE_]);

int main()
{
  int array[10][10];
  foo(array);

  return 0;
}

void foo (int array[][_MAXSIZE_])
{
   array[0][0] = 1;
}

 

[jxxnorth]

thank you!

now if I wanted to assign the passed array pointer to a member variable of a class or another variable,how should I declare it?

int m_intArray [][20];
//-or-
int* m_intArray[20];

...

void foo (int array[][_MAXSIZE_])
{
m_intArray = array; //this is giving me troubles w/ the declared type

//and then

m_intArray[0][0] = 1
}

I'm trying to save this pointer so that it doesn't need to be passed in for other member functions. Thanks in advance!

 

[Leibnitz]

try to use this:

#include<string.h>
#define _MAXSIZE_   20
#define arrcpy( a, b )  memcpy( &a, &b, sizeof(a))//array copy


typedef int Array[_MAXSIZE_];

void foo (int array[][_MAXSIZE_]);

class Someclass
{
public:
	Someclass( int size );
	~Someclass();
	
	Array* m_intArray;
};

Someclass::Someclass( int size )
{
	m_intArray = new Array[size]; 
}

Someclass::~Someclass()
{
    //if(m_intArray)
	//delete [] m_intArray;	 
}

int main()
{
  int array[10][20];
  foo(array);

  return 0;
}

void foo (int array[][_MAXSIZE_])
{
    Someclass t(10);
	
	arrcpy( t.m_intArray, array );

	//and then
	t.m_intArray[0][0] = 1;
}

 

[jxxnorth]

if I understand this correctly, t.m_intArray is still just a copy. My goal is to copy the pointer to the original 2D array so that member functions of several classes can access the same chunk of 2D data - not copies. My fall back is to do the following:

int array[200];

array[y*20 + x] = 1;
//equiv of
//int array[10][20];
//array[y][x]= 1;

because array can be passes easily as int*, but my current code is written for a 2D rather than 1D array.

//foo(array);

//void foo(int* array){}