Function prototype question

[xailer]

hi,Im learning c from a book written prior to today's ANSI standard and I noticed some things are quite different

1-Must a function which is called in a file before
it is defined,be declared with function prototype?

2-Can a Function prototype be declared in each function that calls this particular function,instead of being declared in the beginning of the file?

3-How about function that is defined before it is declared?
Is then function prototype not needed?

thank you

 

[Salem]

> Im learning c from a book written prior to today's ANSI standard
Get one that is for ANSI-C then. It may be of academic interest, but it's not for learning modern C from.

1. Yes
Declaring prototypes for everything irrespective of ordering of functions is the normal thing to do. You can get a quick overview of what the whole file is about simply from looking at the short list of prototypes at the start.

2. Yes
But doing so just creates a big maintenance problem in keeping them all consistent.

3. No.
But see comment on 1.

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[xailer]

hi

>>Get one that is for ANSI-C then. It may be of academic interest, but it's not for learning modern C from.

I assumed most of the things didn't change.Am I wrong?

So the order functions are defined in a file does matter?

thank you for your help

 

[Salem]

> I assumed most of the things didn't change.Am I wrong?
Well a for loop still looks like a for loop, but there are quite a few smaller differences which you need to be aware of.
Function prototypes are perhaps the single biggest visible change from traditional C

> So the order functions are defined in a file does matter?
Only if you don't prototype everything in advance


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[xailer]

hi

thank you very much for helping