Passing an array to a function by reference/pointers

[Ohmu]

Hi!

How to pass an (multidimension al)array of something to a function with
reference/pointer?

Can anyone help me with that?

Thanks,
Ohmu

[John Harrison]

"Ohmu" <oh***@hot.ee > wrote in message
news:37******** *************** ***@posting.goo gle.com...

Hi!

How to pass an (multidimension al)array of something to a function with
reference/pointer?

Can anyone help me with that?

Thanks,
Ohmu

Here's how to prototype and call functions with arrays, references and
pointers.

// one dimension with pointer
void function(int *a);
int array[10];
function(array) ;

// two dimensions with pointer
void function(int (*a)[20]);
int array[10][20];
function(array) ;

// three dimensions with pointer
void function(int (*a)[20][30]);
int array[10][20][30];
function(array) ;
// one dimension with reference
void function(int (&a)[10]);
int array[10];
function(array) ;

// two dimensions with reference
void function(int (&a)[10][20]);
int array[10][20];
function(array) ;

// three dimensions with reference
void function(int (&a)[10][20][30]);
int array[10][20][30];
function(array) ;

john

[Ohmu]

"John Harrison" <jo************ *@hotmail.com> wrote in message news:<bi******* *****@ID-196037.news.uni-berlin.de>...

Here's how to prototype and call functions with arrays, references and
pointers.

// one dimension with pointer
void function(int *a);
int array[10];
function(array) ;
<snip> // one dimension with reference
void function(int (&a)[10]);
int array[10];
function(array) ; <snip>
john

but how to pass the array when the size is read from file, int array[size][size] ??

Ohmu

[John Harrison]

"Ohmu" <oh***@hot.ee > wrote in message
news:37******** *************** ***@posting.goo gle.com...

"John Harrison" <jo************ *@hotmail.com> wrote in message news:<bi******* *****@ID-196037.news.uni-berlin.de>...

Here's how to prototype and call functions with arrays, references and
pointers.

// one dimension with pointer
void function(int *a);
int array[10];
function(array) ;

<snip>

// one dimension with reference
void function(int (&a)[10]);
int array[10];
function(array) ;

<snip>

john

but how to pass the array when the size is read from file, int

array[size][size] ??
Ohmu

int array[size][size]; is not a legal array declaration.

If your 2d array is dynamic then you need to allocate some memory for it and
use pointers. E.g.

void function(int** a);

int **array;
array = new int*[size];
for (int i = 0; i < size; ++i)
array[i] = new int[size];
function(array) ;

This question is in the FAQ

http://www.parashift.com/c++-faq-lit...html#faq-16.15

john