C TYS

[[Gandalf]]

Nope, no edit button in help forums because it was abused.

wtd wrote:

Much simpler than that, Gandalf.

Do you understand how the strcpy function works?

Well, I assumed so. Even simpler than Andy's too? Something with recursion maybe?

And yes, I'm quite confident in my understanding of your strcpy function.

[md]

c++:

char *cat(char *dest, char *src) {     while( *dest ) dest++;     while( *dest++ = *src++ ) ;     return dest; }

please excuse any typos... beer makes typing hard.

[Andy]

ohh, multiple lines! lol.

md, you cant return a pointer when your functions shifts it. but i'm sure that was just the beer thinking =P

[bugzpodder]

Andy wrote:

tsk tsk gandalf...

c++:

void strcat(char *dest, char *src) {     while (*dest++ = (*dest)?*dest:*src++); }

tsk tsk Andy...

c++:

while ((*d++) || *d = *s++);

[Monstrosity_]

Andy wrote:

md, you cant return a pointer when your functions shifts it.

And why not?

[md]

Andy wrote:

ohh, multiple lines! lol.

md, you cant return a pointer when your functions shifts it. but i'm sure that was just the beer thinking =P

Sure you can! though it should really be return dest--;

I think bugzpodder's code is the shorted however...

[wtd]

md wrote:

I think bugzpodder's code is the shorted however...

And yet represents more of a change than the code I demonstrated to you.

[bugzpodder]

the correct code should actually be:
[syntax]
while(*++d||(*d=*s++));
[/code]

because of a subtlety *++d is evaluated from left to right, so d gets deferenced first then increased

Quote:

And yet represents more of a change than the code I demonstrated to you.

What do you mean?

[Monstrosity_]

bugzpodder wrote:

the correct code should actually be:
[syntax]
while(*++d||(*d=*s++));
[/code]

because of a subtlety *++d is evaluated from left to right, so d gets deferenced first then increased

The grouping for those two is right to left, (*(++d)). If it were (++(*d)), where d gets dereferenced first then incremented, then your stuck in loop where the pointer never changes.

Also, your increments in both examples would skip assigning/checking to the first value in the array. Try with d as an empty string.

wtd wrote:

md wrote:

I think bugzpodder's code is the shorted however...

And yet represents more of a change than the code I demonstrated to you.

Hmm, I'm interested in what yours could be now. I would have just added another line to the strcpy function.

[bugzpodder]

I was too greedy. Tried to put everything in the conditional statement.

code:

while(*d||(*d=*s++))d++;

Take that, punk!

[bugzpodder]

and before anyone claims andy's code is shorter, both code sets has comparable character counts, and my code do |d| less assignments than andy's code

[wtd]

code:

void strcat(char *dest, char *src) {    while (*dest) dest++;    while (*dest++ = *src++); }

This represents a very minimal change to the strcpy function as provided.

[Monstrosity_]

wtd wrote:

code:

void strcat(char *dest, char *src) {    while (*dest) dest++;    while (*dest++ = *src++); }

This represents a very minimal change to the strcpy function as provided.

I would have done

code:

void strcat(char *dest, char *src) {    dest += strlen(dest);    while (*dest++ = *src++); }

same deal, just function call over head ;p

[bugzpodder]

then you might as well use memcpy

[wtd]

Monstrosity_ wrote:

code:

void strcat(char *dest, char *src) {    dest += strlen(dest);    while (*dest++ = *src++); }

This actually won't work.

Anyone care to guess why?