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From: geoff@cs.warwick.ac.uk (Geoff Rimmer)
Newsgroups: comp.lang.c
Subject: Re: printf() problem
Message-ID: <1783@ubu.warwick.UUCP>
Date: 28 Apr 89 03:13:45 GMT
References: <11657@hodge.UUCP>
Sender: news@warwick.UUCP
Organization: Computer Science, Warwick University, UK
Lines: 50
In-reply-to: jdm@hodge.UUCP's message of 26 Apr 89 00:25:48 GMT

In article <11657@hodge.UUCP> jdm@hodge.UUCP (jdm) writes:

> 	   printf("%x %x %x %x\n", getc(fp), getc(fp), getc(fp), getc(fp));
> 
>  Although the order of the data in the file is:
> 
> 	   92 AB 4E 33
> 
>  printf() displays it as:
> 
> 	   33 4E AB 92
> 
>  Just the reverse of its order in the file.

The 5 arguments to printf() are being pushed onto the stack, starting
from the 5th back thru the 1st (the format string).  There is nothing
odd with this.  When a C compiler is written, the author can evaluate
arguments to functions in anyway he/she likes.  Last to first, first
to last, or even the even arguments followed by the odd ones!

So, you should never have the code:

main()
{
    int i=1;
    printf("%d %d %d %d\n",i++,i++,i++,i++);
}

since some compilers will print
	1 2 3 4
others will print
	4 3 2 1
an a weird one might print
	3 2 1 4

So, you cannot and must not rely on any particular behaviour.  What
works for your compiler may not work with another.

Geoff

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