Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!rutgers!ames!ucbcad!ucbvax!decvax!tektronix!uw-beaver!ssc-vax!shuksan!tahoma!fawcett
From: fawcett@tahoma.UUCP
Newsgroups: comp.lang.c
Subject: c question
Message-ID: <131@tahoma.ARPA>
Date: Thu, 12-Feb-87 17:17:45 EST
Article-I.D.: tahoma.131
Posted: Thu Feb 12 17:17:45 1987
Date-Received: Sun, 15-Feb-87 15:46:18 EST
Organization: Boeing Commercial Airplane Co., Seattle, WA
Lines: 32
Keywords: char, casting, printf

I have come across something that I did not expect to find.  I was trying
to print out a special character to the terminal and got a response other
that what I expected.  The code I used was:

main()
{
	union
	{
		char full_message;
		int _message;
	}u;	

	u.full_message = 0xaa;

	printf("%10x\n", (int)u.full_message);
	printf("%10x\n", u._message);
}

What I got when I ran this was:

  ffffffaa
  aa000000

I have tried various other methods for doing this to no avail.
When I tried to print the number as an integer, it worked as expected.
Does anyone know what I am doing wrong, or help me to understand why I got
this response.

John W. Fawcett				Voice: (206) 237-5080
Boeing Commercial Airplane Company	UUCP: ..!uw-beaver!ssc-vax!shuksan
P.O. Box 3707, M/S 66-04			!tahoma!fawcett
Seattle, WA  98124-2207