Thread: pointer to pointer ok?

Hi,

I remember reading a while back that pointers to pointers was in some way bad programming practice:

e.g. A string swapping function

Code:

void swap(char** a, char ** b)
{
char * temp = *a
*a = *b
*b = *a
}

Could someone tell me why again please?

Thanks

I dont believe it is bad programming practice at all. In fact in c its necessary if you need to pass a pointer to a function by reference rather than by value.

"inline" is a instruction to the compiler. What it says is instead of jumping to the code of a function when you call it, it copies the code inside that function there instead......

This can be much quicker as each time you call a function, certain code must be produced to allow your code to pass parameters, set up stack frames and then return when the function is done...with an inline you can get away from this overhead.......It should only be used for small functions though....your compiler might not allow you to use it for large functions

Originally posted by The Dog
IMO, there's nothing wrong with having pointers to pointers.

It's perfectly legal in C and I use it all the time. The problem is that other people who read such code won't be able to grasp it very easily.

One example is instead of returning a pointer to a new address, assign the new address in the function. All those indirection operators, '*', would make the code look ugly. But on the other hand, if you're the only one who's gonna read the code, then you can have all the pointers you like.

if a programmer cannot understand double-pointers, then it's his problem, not yours. i mean, main() takes a double-pointer (unless you don't want to use commandline params)!! it's a pretty common concept.

Originally posted by Fordy
"inline" is a instruction to the compiler. What it says is instead of jumping to the code of a function when you call it, it copies the code inside that function there instead......

It should be noted that C has no 'inline' keyword. This is a C++ feature.

Quzah.

and an (of course non-portable) extension on some C compilers

Originally posted by quzah
It should be noted that C has no 'inline' keyword. This is a C++ feature.

Quzah.

Hmm......I thought it was added with C99 (I could well be wrong, but that's the impression I had)...but then I dont know what compilers are out there that comply to this anyway.....