Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: A trivial XOR doubt in a program
Top Forums Programming A trivial XOR doubt in a program Post 302247330 by jim mcnamara on Wednesday 15th of October 2008 12:05:00 PM
Old 10-15-2008
The short answer - it is an undefined operation. Means that the C standard regards this as garbage, and your compiler was polite enough to produce spaces.
The reason: there are no sequence points in the line between important steps.

A ; character creates a sequence point. So the first version works. This means the compiler can do any of those calculations in any order...

By the way, that 'swap' algorithm in general is a bad idea; it has unsafe properties. You should use a temp variable. It may look cool to you, but that is about it.
 

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

trivial awk question

i posted a reply the other day and needed an answer to this question while i was clarifyiing a few matter.. "how to compare to date variable in string format without having to compare word for word".. my reply was to try to use awk to compare the strings.. I wasn't quite sure if i remembered how... (2 Replies)
Discussion started by: moxxx68
2 Replies

2. Programming

resetting counter using bitwise XOR

Hi ! How to reset a variable to 0 after a reset value, say 10 using bitwise XOR. For example, int cnt=0; if(cnt<10) cnt++; else cnt = 0; How can we achieve this by using XOR only. thanks, (1 Reply)
Discussion started by: mrgubbala
1 Replies

3. Shell Programming and Scripting

xor 2 values in ksh?

i have to xor two variables in ksh. how to do that? tia, DN2 (5 Replies)
Discussion started by: DukeNuke2
5 Replies

4. Shell Programming and Scripting

Doubt in this trivial awk code

Hi, What is the difference in the following two awk one-liners? awk -F, '{s++} END {if (s == 1 && $4 > "09:10:00") {print $2, $4}}' f1 awk -F, '{s++} s == 1 && $4 > "09:10:00" {print $2, $4}' f1 Even though, all the 2nd column values have duplicate records, the first code does not give any... (4 Replies)
Discussion started by: royalibrahim
4 Replies

5. Shell Programming and Scripting

Trivial perl doubt about FILE

Hi, In the following perl code: #!/usr/bin/perl -w if (open(FILE, "< in_file")) { while (<FILE>) { chomp($_); if ($_ =~ /patt$/) { my $f = (split(" ", $_)); print "$f\n"; } } close FILE; } Why changing the "FILE" as... (4 Replies)
Discussion started by: royalibrahim
4 Replies

6. Programming

Trivial doubt about C function pointer

Hi, In the below C code, #include <stdio.h> void print() { printf("Hello\n"); } int main() { void (*f)() = (void (*)()) print; f(); (*f)(); } I wonder, how the syntaxes "f()" and "(*f)()" are treated as same without any error? Is this an improvement or ANSI/ISO... (1 Reply)
Discussion started by: royalibrahim
1 Replies

7. UNIX for Dummies Questions & Answers

XOR between strings

I am aware of truth table for XOR between binary values . Out of curious in would like to know how XOR works between 2 strings which contain alphabets . For example A ^ B How it works internally? Please help me to understand this Thanks (1 Reply)
Discussion started by: pandeesh
1 Replies

8. FAQ Submission Queue

Analysis in bitwise XOR

The purpose of this article is revealing the unrevealed parts of the bitwise XOR. As we aware, the truth table for the XOR operator is : A B A^B 0 0 0 0 1 1 1 0 1 1 1 0 For example , 1^2 will be calculated as given below: First the operands... (1 Reply)
Discussion started by: pandeesh
1 Replies

9. UNIX for Dummies Questions & Answers

XOR two strings

hi, i am new to shell programming, can u please tell me how to perform XOr operation of two strings. i tried to do xor using ^symbol but this doesnt work. help me with this Thanks (12 Replies)
Discussion started by: anil_uvce
12 Replies

LEARN ABOUT MINIX

ppmtosixel

ppmtosixel(1)                                                 General Commands Manual                                                ppmtosixel(1)

NAME

       ppmtosixel - convert a portable pixmap into DEC sixel format

SYNOPSIS

       ppmtosixel [-raw] [-margin] [ppmfile]

DESCRIPTION

       Reads  a  portable  pixmap  as input.  Produces sixel commands (SIX) as output.  The output is formatted for color printing, e.g. for a DEC
       LJ250 color inkjet printer.

       If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled.  A printer control header and a color assignment table
       begin the SIX file.  Image data is written in a compressed format by default.  A printer control footer ends the image file.

OPTIONS

       -raw   If  specified,  each  pixel  will  be explicitly described in the image file.  If -raw is not specified, output will default to com-
              pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands.  A raw file is often an order  of  magni-
              tude larger than a compressed file and prints much slower.

       -margin
              If  -margin  is not specified, the image will be start at the left margin (of the window, paper, or whatever).  If -margin is speci-
              fied, a 1.5 inch left margin will offset the image.

PRINTING

       Generally, sixel files must reach the printer unfiltered.  Use the lpr -x option or cat filename > /dev/tty0?.

BUGS

       Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion.  If the original PPM maxval was
       greater  than  100,  rescaling  also reduces the image depth.  While the actual RGB values from the ppm file are more or less retained, the
       color palette of the LJ250 may not match the colors on your screen.  This seems to be a printer limitation.

SEE ALSO

       ppm(5)

AUTHOR

       Copyright (C) 1991 by Rick Vinci.

                                                                   26 April 1991                                                     ppmtosixel(1)
All times are GMT -4. The time now is 02:21 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy