NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c-part1/6853

Text File | 1996-08-05 | 2.1 KB | 64 lines

Path: sun001.spd.dsccc.com!spd!jmccarty
From: [e-mail] (Mike McCarty)
Newsgroups: comp.lang.c
Subject: Re: Confusion as to the proper use of MODULAS
Date: 15 Feb 1996 19:24:27 GMT
Organization: DSC Communications Corporation, Plano, Texas USA
Message-ID: <4g019b$[e-mail]>
References: <4fr8be$[e-mail]> <[e-mail]> <4fthsu$[e-mail]>
NNTP-Posting-Host: aplo139.spd.dsccc.com

In article <4fthsu$[e-mail]>, KPN  <[e-mail]> wrote:
)Confusion as to the proper use of MODULAS
)
)Very confused. Just as I think IÆve got it correct, I make-up a new
)test, the results of which leave me mixed-up again.
)
)To begin with, this is the first rule I found out:
)
)Modulas operator simply shows:  *** AFTER *** you divide, what is the
)remainder?
)EXAMPLE of this:
)    9 % 7 = ?
)    9 divided by 7 yields a remainder of 2
)    9 % 7 = 2
)
)1) MODULAS means divide a number and give me the left over number. OK -
)not bad.

[snip]

)Here, begin my troubles: using MODULAS in an IF statement.
)
)I made up a test to see if a number I inputted was a 7. Sample code:
)
)   if (number % 7)
)      printf("Not a 7\n");
)   else
)      printf("First integer was a 7\n");
)
)So, if the number WAS a 7, the ELSE would take over. OK. But, when I
)enter in a ZERO, it still tells me that the number was a seven?
)
)Am I going in the right direction? Can someone tell me what IÆm doing
)incorrectly, or where IÆm straying? WhatÆs the rule here for using MOD
)in an IF statement?

You used it just fine. You just still don't exactly understand what a
remainder is. You are testing for divisibility. Zero (0) is exactly
divisible by 7 (or any other non-zero number, for that matter), with no
remainder. In fact,

    0 = (0)(7)+(0)

And since |0| <= |0| (absolute of remainder less or equal to absolute of
divisor), 0 is the remainder.

So 0 is a multiple of 7. So is 14. So 14 % 7 is 0.

Mike
----
char *p="char *p=%c%s%c;main(){printf(p,34,p,34);}";main(){printf(p,34,p,34);}

I don't speak for DSC.         <- They make me say that.