Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!ephemeral.ai.toronto.edu!bradb
From: bradb@ai.toronto.edu (Brad Brown)
Newsgroups: comp.lang.c
Subject: Re: printf() problem
Keywords: C printf
Message-ID: <89Apr26.201617edt.10785@ephemeral.ai.toronto.edu>
Date: 27 Apr 89 00:16:13 GMT
References: <11657@hodge.UUCP>
Organization: Department of Computer Science, University of Toronto
Lines: 34

In article <11657@hodge.UUCP> jdm@hodge.UUCP (jdm) writes:
>
>    I have a file with binary data.  I want to read four consecutive
>    bytes from the file and display them with printf().  The data
>    in in the file in hex is:
>
>        92 AB 4E 33
>
>    I fopen() the file in binary mode and used the following line
>    of code to read and print out the data:
>
>        printf("%x %x %x %x\n", getc(fp), getc(fp), getc(fp), getc(fp));
>
>    Although the order of the data in the file is:

C makes no guarantees about the order in which arguments are evaluated --
K&R says this and several other places do to.  That's why you CAN'T 
have functions with interdependant side effects in the argument list
of a function call -- you can't say which one will execute first.

Unfortunately your solution 

>        a = getc(fp);
>        b = getc(fp);
>        c = getc(fp);
>        d = getc(fp);
>
>        printf("%x %x %x %x\n", a, b, c, d);

is (an) appropriate one because you have to get consecutive reads out of
the argument list.

					(-:  Brad Brown  :-)
					bradb@ai.toronto.edu