Hi,
I get the basics of pointers, but as soo as they get more complex I'm stuck. For example, even the printf function:
int printf ( const char * format [ , argument , ...] );
What do they mean by const char *, so a pointer to a string? I allways have problems with things like this.
When you pass an array to a function, it degrades into a pointer to its first element. The first argument for printf, the format string, is treated like an array of char.
printf could have been implemented like this:
printf( const char format[] [, variable... ] );
printf( const char *format [, variable... ] );
To the compiler it all looks the same.
Yeh but I mean if I just do
printf("Whatever");
'Whatever' itself isnt stored as a variable, so its not stored in memory (is it?), so how can you "point" to it?
>When you pass an array to a function, it degrades into a pointer to its first element.
That's mean. What makes an array so special that it "degrades" into a pointer? Is the array slumming? Are you suggesting that pointers are gutter trash? You'd better apologize, I think you hurt the pointer's feelings.
>'Whatever' itself isnt stored as a variable, so its not stored in memory
Of course it's stored in memory, otherwise it wouldn't exist at all.
>so how can you "point" to it?
One of the biggest benefits of pointers is the ability to refer to anonymous memory.
My best code is written with the delete key.
> You'd better apologize, I think you hurt the pointer's feelings.
I do apologize... I need to look up some less loaded words in English. >.>
> 'Whatever' itself isnt stored as a variable, so its not stored in memory (is it?)
It is stored in memory. The printf function (like other functions) will allocate enough stack space for its arguments once it is called, since a function's arguments are a part of its stack frame. So even if you write something like
printf( "hello world\n" );
the string is still stored somewhere. The C compiler is pretty smart in that regard. It's part of all the little things that happens thanks to machine code generated by MinGW (or whatever you use).
Last edited by whiteflags; 07-31-2006 at 03:02 PM.
Ok thanks I tink I understand it more now... but I still have problems with some functions that have complicated pointers. Cant think of any right now but Il get back to you
Quzah isn't adverse to saying that pointers degrade: http://cboard.cprogramming.com/showp...6&postcount=10
dwk
Seek and ye shall find. quaere et invenies.
"Simplicity does not precede complexity, but follows it." -- Alan Perlis
"Testing can only prove the presence of bugs, not their absence." -- Edsger Dijkstra
"The only real mistake is the one from which we learn nothing." -- John Powell
Other boards: DaniWeb, TPS
Unofficial Wiki FAQ: cpwiki.sf.net
My website: http://dwks.theprogrammingsite.com/
Projects: codeform, xuni, atlantis, nort, etc.
Boozers and tramps.
Quzah.
Hope is the first step on the road to disappointment.
>Quzah isn't adverse to saying that pointers degrade:
Yet quzah is an uncivilized brute.Speaking of, how does one pronounce quzah?
My best code is written with the delete key.
kuh - zaw? I have never wondered about the name, but that avatar always made me wonder. What is it?
OMG! It's Cobra Commander from GI Joe! His old sig was a dead giveaway, given that it actually showed that it was a Cobra Commander quote
If you understand what you're doing, you're not learning anything.
lol - I would not know GI Joe stuff if it hit me in the face.
I think we can officially call this a hijack.
Quzah.
Hope is the first step on the road to disappointment.
>lol - I would not know GI Joe stuff if it hit me in the face.
I still have no idea what GI Joe is. I know that it was some kind of army thing, and the boys in my neighborhood couldn't get enough of the little action figures. Apparently there was a lame cartoon too, but that's the extent of my interest.
My best code is written with the delete key.
The best part was the 5 minute "Now you know" segment at the end of each episode.Apparently there was a lame cartoon too
If you understand what you're doing, you're not learning anything.
