guys,
what does this definition mean?
Code:
please enlighten me
baray98
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guys,
what does this definition mean?
Code:
please enlighten me
baray98
Quote:
Originally Posted by baray98
It means that grid - is a pointer which points at another pointer that points at one more pointer on MyGrid object.
I've never seen a triple pointer before, but there's no reason why not. A double pointer is somewhat common, it means a pointer to a pointer. Why would you want a pointer to a pointer? Consider c-style strings.
char *mystring
char **ptr2mystring;
Also, arrays are really pointers to the first element of the array. So a common idiom is to write the following:
int main(int argc, char* argv[])
which is an array of strings as...
int main(int argc, char** argv)
But a triple pointer is much rarer. I would avoid it for the confusion it would cause. I would also avoid double pointers in C++ code, though they might be necessary in C code.
It is not possible to say what the intention of a triple pointer is from the pointer itself - because C does not distinguish between pointers and arrays.
It might be something not such sensible as the adress of the address of the adress of some object.
Or it might be: a 3-dim array.
int x; // an integer
int *x; // address of an integer OR first element of an array (size unknown)
int **x; // address of adress of integer; or address of array of int; or array of arrays of int
int ***x; // ... or array of array of array of int
(Note that the following is not correct
int field[10][5][3];
int ***x = field;
an array of pointers is how one realizes in low-level, plain C a dynamic array of unknown size. Note that the rows may have different sizes: each is the result of a malloc with potentially different length.
These things are not difficult but error prone. Therefore I recommend to stay clear of this and use C++/Qt containers when possible.)