for loop, two different types

[vippstar]

Hello comp.lang.c

I had to write a for() loop with two temporary variables for it.
What I *usually* do is define the variables at the top so it works in
C89 as well.
But I realized that it just can't be done in the C99 'for' loop!

Assume I want two variables, int i and size_t size.

for(int i, size_t size; ...; ...)

is a syntax error

Is there a way to do this? I'm not talking about putting these two
types in a struct.

Assuming this can't be done, isn't the addition of defining variables
in the first part of the for loop in C99 useless, or at least
"incomplete"?

 

[santosh]

Hello comp.lang.c

I had to write a for() loop with two temporary variables for it.
What I *usually* do is define the variables at the top so it works in
C89 as well.
But I realized that it just can't be done in the C99 'for' loop!

Assume I want two variables, int i and size_t size.

for(int i, size_t size; ...; ...)

is a syntax error

Is there a way to do this? I'm not talking about putting these two
types in a struct.

Assuming this can't be done, isn't the addition of defining variables
in the first part of the for loop in C99 useless, or at least
"incomplete"?

Well you can't do:

int i, size_t size;

anywhere else either.

 

[vippstar]

<Shrug.> Define "complete," and then we can all have fun
mocking you for the things you overlooked. ("That silly vippstar!
His so-called `complete for' doesn't permit function definitions
inside the increment portion. What a shortsighted moron, tee-hee!")

I guess I'm just looking for things I found in other languages that in
C wouldn't make sense
(I'm talking about the common lisp 'LOOP' macro)

Regardless - this particular problem wasn't important to me, I was
just curious why such thing wasn't allowed and now I believe I
understand.

 

[santosh]

I guess I'm just looking for things I found in other languages that in
C wouldn't make sense
(I'm talking about the common lisp 'LOOP' macro)

Regardless - this particular problem wasn't important to me, I was
just curious why such thing wasn't allowed and now I believe I
understand.

I think C99 allows a single declaration in the initialisation part of
the for loop. What you wanted were multiple declarations, which would
require multiple statements, and that is a syntax error in a for loop.
It would have been nice if it were legal though - no need for ugly
blocks.

 

[Ron Ford]

Hello comp.lang.c

I had to write a for() loop with two temporary variables for it.
What I *usually* do is define the variables at the top so it works in
C89 as well.
But I realized that it just can't be done in the C99 'for' loop!

Assume I want two variables, int i and size_t size.

for(int i, size_t size; ...; ...)

What happens in the body of the loop with i and size such that your syntax
would be different than garden-variety nested loops?