Tips, Tricks and Tools

Firefox extension: Full Screen Image Viewer

2012-01-19T23:57:00.006-05:00

You can easily view images of a page in full screen with Full Screen Image Viewer extension. Just right-click on the Firefox browser and find the *Full Screen Image Viewer* item from the Context Menu. The Image Viewer can also open the image links on a web page or your local disk. You can use it as a local image viewing application. Control Buttons After you click on the *Full

Javascript: setting image width/height in pixels, cannot use "px"

2012-01-17T21:26:00.000-05:00

The *img* element has its own width and height property. You can resize an image by setting its width and height property or by setting its style property, e.g. imageElement.width = "100"; or imageElement.style.width = "100px";They both resize the width of the image to 100 pixels.You may notice that one is set with "px" at the end, the other is without. If you try the following code,

Firefox extension programming: insert an image to the document

2012-01-14T14:08:00.000-05:00

The Firefox extension can insert things to the document you are viewing. This document (or web page) is not the one the Firefox extension is referring as the *document* element. To access it, one of the methods is to use: var doc = getBrowser().contentWindow.document;Now *doc* is the document object of the current page in the content window.To insert a paragraph to the bottom of the current

Lightbox without jQuery -- soooooooo simple

2012-01-06T22:44:00.001-05:00

Lightbox is like a modal dialog which usually pops up to display images. It looks fancy and more websites are now using it. Most of the tutorials on creating a Lightbox is by using jQuery. But the magic of Lightbox has nothing do with jQuery. It is the *CSS position property* that plays the key. All you need are two things: 1) a style sheet for the lightbox: .lightbox { position:fixed;

Git for Windows

2012-01-03T21:58:00.000-05:00

I was looking for a version control system that runs on Windows recently. Git seemed to be a very good candidate. It is a distributed system which works very well and naturally on a standalone machine. The Windows flavor is called msysgit. I downloaded the portable version of it. It is packed by 7zip and does not require installation. Just extract the files and folders to a new folder you want.

Share Buttons Bar

2011-12-13T23:22:00.057-05:00

As you can see in the bottom left corner of this page, the Share Buttons Bar embeds the most popular share buttons from Internet. Your readers can shrink or expand the Bar by click on the rightmost button. If you are interested to add the Share Buttons Bar to your web site, it is very simple. Just copy the following two pieces of code to the appropriate place. Before doing it, you should

Python: a simple HTTP client

2011-12-09T21:45:00.000-05:00

1 import httplib 2 3 h = httplib.HTTPConnection('www.python.org') 4 h.request('GET', '') 5 r = h.getresponse() 6 7 rh = r.getheaders() 8 print 'Header:' 9 for i in rh: 10 print i[0], ':', i[1] 11 print '\n' 12 13 rr = r.read() 14 print 'Content:' 15 print rr 16 print '\n' 17 18 h.close() The httplib module

Add the Google +1 button to your website

2011-12-08T23:57:00.007-05:00

Google has made it very convenient to add the Google +1 button to your website. What is shown above is the default style of the Google +1 button you can get from http://www.google.com/intl/en/webmasters/+1/button/index.html. Just make a couple of clicks and you can get the code to copy to your website. Tip 1: If you want to add multiple Google +1 buttons that +1 different URLs, you need

Google Chrome extension: Bulk Player Mate

2011-10-22T23:42:00.000-04:00

Bulk Player for YouTube is an online tools that let you play a list of YouTube videos continuously. After one video is done playing, the next one will be played automatically without your intervention. It is useful when you want to play a bunch of YouTube musics or watch a program in series from a distance -- e.g. you have a big display, or your computer is connected to a TV. Bulk Player for

Name change of one Firefox extension

2011-09-13T22:37:00.000-04:00

The name of our Firefox extension Google Dictionary and Google Translation is changed to Wiktionary and Google Translation in version 3.0. As many of you have noticed, the Google Dictionary service (http://www.google.com/dictionary) was shut down not long ago. Consequently, some function of the Google Dictionary and Google Translation extension stopped working -- the old version of the extension

IE Extension: Bulk Player Mate for YouTube

2011-05-22T16:27:00.001-04:00

This IE extension lets you play all or any of the YouTube video links on a page by just several clicks. For example, if we want to watch some videos of Shania Twain, we can go to www.youtube.com and input Shania Twain into the search box. We would get so many results. To narrow it down, we input the owner's name as well -- Shania Twain by ShaniaTwainVEVO. Now we get some videos as the search

A very simple example of Internet Explorer addon development

2011-05-13T18:26:00.007-04:00

This is not a complete tutorial. It shows how easy it is to build an IE addon/extension in just 5 minutes. And it does not stop you from building a far more complex addon with the other mechanisms. This example adds a menu item to the default context menu of IE. When right click on IE, the user can see the new menu item and click on it. A dialog pops up showing the title of the Web page you are

Windows XP: add a Lock Screen icon to the desktop and the Quick Launch bar

2011-05-02T22:58:00.001-04:00

Follow these steps: Right click on the desktop. Select New|Shortcut on the context menu. Input "rundll32.exe user32.dll, LockWorkStation" (without the quotes) as the location of the shortcut. Choose a name for the icon, e.g. Lock Screen. After the shortcut is created on the desktop, you can change its icon by right click on it and select Properties, and click on the "Change Icon ..." button.

CVS: merge changes in trunk to branch

2011-03-25T20:44:00.006-04:00

After you have made some changes in the trunk, you can merge those changes into a branch with the following steps. Tag the code before you make the changes in the trunk, e.g. TAG_TRUNK_BEFORE_CHANGES. (If you have forgot to do the tagging, see how to do it at the end.) cvs tag TAG_TRUNK_BEFORE_CHANGES Change the code. Tag the code after the changes in the trunk, e.g

Random Posts Widget for Blogger

2011-03-11T20:58:00.004-05:00

This widget is for Blogger.com. It randomly digs up your posts and lists them on every posts of your blog. This helps to give your old posts more exposure. You can see the live example in the side bar (on the right side) of this page. Each time you reload the page, the Random Posts section displays the titles of different posts. To install the widget, just click the icon below and follow the

Find out what WiFi channels your neighbors use and avoid interference

2011-03-07T19:21:00.000-05:00

As you may have known, it is recommended to choose a channel among 1, 6, 11 for your wireless network. You can also choose other channels and actually some people do. But that is not doing good to your and other wireless networks. Why 1, 6, 11 are recommended? Because these channels do not intervene with each other. The air is getting more and more crowded. Chances are some of your neighbors

Google Dictionary and Google Translate extension is blocked by Flashblock

2011-03-04T18:11:00.001-05:00

One of the feature, the whole page translation feature of the Google Dictionary and Google Translate extension for Firefox does not work when the Flashblock extension is installed and enabled. After some investigation, I found out that some functions of the Google Translate service is not working if the Flashblock extension is in effect. Our Google Dictionary and Google Translate extension can do

Blogger: move Adsense to the end of post and above comments

2011-02-23T21:12:00.003-05:00

When hosting your blog at blogspot.com, it is very easy to add Ads to your blog. Just go to the Dashboard, click on the Monetize tab and follow the instructions. You could add Ads at the end of each post and the sidebar. But there is a major "flaw" of adding the Ad to the end of the post. The Ad is added below the comments. When your readers are reading that single post (not the homepage of the

Firefox Extension: Packed Menu 2 Nav

2011-02-16T21:21:00.004-05:00

(For Firefox 4 only.) This extension is very similar to another extension Packed Menu except that it puts the button on the Navigation Toolbar instead of the Menu Bar. This extension conflicts with the extension Packed Menu, so I self-host it. You must read this and uninstall Packed Menu before you can use this extension. This extension adds a button "M" to the Navigation Toolbar. And the

Google Chrome: What to do if a problematic extension crashes Chrome

2011-02-10T18:23:00.001-05:00

If after you install an extension, your Chrome can not start and run, you want to run Chrome in a safe mode so that you can disable the extension which causes the problem. Method 1 Right click on the icon of the Chrome, and select Properties on the context menu. In the Shortcut tab, look for the Target box. Append the argument "--incognito" to it. It will then look like: "C:\\...\Google

What happened to the Chrome extension Boss Key and Button

2011-01-31T22:01:00.000-05:00

Just got a comment on the post Google Chrome extension Boss Key and Button, and knew that the extension's Options page stopped working. After some investigation, it turned out that the new version of Google Chrome does not support the syntax: It was not only Google's fault. Google

C++ programming: split a string

2011-01-27T19:31:00.000-05:00

We have a string red, green, brown, blue and we want to split it by ", " into four words red green brown blue Method 1 -- the traditional way with the C function strtok() #include #include #include #include #include using namespace std; vector splitString(string input, string delimiter) { vector<

How to change the font and color of the Google Dictionary and Google Translate extension

2011-01-24T21:43:00.001-05:00

In the version 2.0 of the Google Dictionary and Google Translate Firefox extension, you can apply your own style to the dictionary pop-up. You can change the background color, the font family, the font color, or the font size, etc. To do that, you must have some knowledge of CSS (Cascading Style Sheets). If you do not want to bother, you can just choose from the samples we provide. To input your

Style templates for Google Dictionary and Google Translate firefox extension

2011-01-14T21:35:00.013-05:00

In the upcoming version 2.0 of the Google Dictionary and Google Translate firefox extension, users can apply their own style to the dictionary pop-up. This is a highly wanted feature requested in many comments. To do that, go to the extension's Options dialog and click on the "Style" tab; check the "Enable my style" option; and input your CSS code underneath. Yes, the user should know some CSS

ASCII <--> EBCDIC Online Converter

2011-01-05T21:40:00.001-05:00

(Beta version) var asciiList = [ 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',

Firefox Extension: Bulk Player Mate for YouTube

2010-12-29T18:59:00.008-05:00

This extension lets you play all or any of the YouTube video links on a page by just several clicks. For example, if we want to watch some videos of Shania Twain, we can go to www.youtube.com and input Shania Twain into the search box. We would get so many results. To narrow it down, we input the owner's name as well -- Shania Twain by ShaniaTwainVEVO. Now we get some videos as the search result

Linux ACPI issue

2010-12-28T19:57:00.007-05:00

In a previous post, I had a temporary solution for the ACPI issue of the kernel on my machine. It worked but the machine hesitated all the time. Recently, I played with the kernel parameters related to the ACPI and got some interesting results. 1. Use the option acpi=off. The auto shutdown problem was gone, but the system became sluggish. 2. Use the option acpi=ht. The result was same as acpi=

Enter multiple paragraphs in a cell of the Google Docs' spreadsheet

2010-12-28T18:13:00.001-05:00

You cannot simply press the Enter button to insert a line break into the cell in the Google Doc's spreadsheet. That would finish the editing of the cell and the next cell would be focused. Instead, you need to press Alt-Enter or Ctrl-Enter

MD5 example in Java

2010-12-06T20:35:00.002-05:00

Both Linux and Windows have tools to compute the MD5 (Message Digest algorithm 5) hash value of a file. In Linux, run md5sum In Windows, run fciv.exe If the tools are not installed, it is very easy to build your own one in Java. Just create a new text file named Md5.java and copy&paste the following code into it. import

How confident is Google about its language detection?

2010-11-30T22:55:00.002-05:00

Google provides a very handy online tool for language detection -- http://www.google.com/uds/samples/language/detect.html. After you input something and hit the Detect Language button, the result is shown below telling you what language Google thinks it is, together with whether Google thinks the result is reliable or not, and how confident it is. The confidence level is between 0-1, so a value

Whole-page translation problem in the early versions of Google Dictionary and Google Translate

2010-11-15T22:18:00.003-05:00

(The issue is fixed in version 1.2.1.) Although I had tested all the supported languages with the whole-page translation feature of the Google Dictionary and Google Translate extension for Firefox, the reviewers said that the whole-page translation did not work at all. This puzzled me for quite some time and I rewrote most of that part of code. The last error they got was an exception of "

Crash, core dump and gdb

2010-11-10T20:11:00.002-05:00

When a linux program crashes, a core file could be generated under the directory where you ran the file. A core file contains very useful information to help you debug the program. If there is no such a file named core.XXXX, it may be that the parameter of the maximum size of core files is set as 0. Check it with this command: $ ulimit -c If the result is 0, set a size for it, e.g. $

Turn off the open captioning

2010-10-18T21:11:00.000-04:00

Closed captioning is a good thing. It helps not only those who have hearing issues, but also those who speak other languages. Open captioning, unlike the closed captioning which can be turned off when you don't need it, is burnt to the video and cannot be turned off. It is sometimes annoying when you want to enjoy the pictures but the subtitle keeps distracting you. It is even more annoying

Java source code of NoCaption

2010-10-18T21:07:00.000-04:00

import javax.swing.JFrame; import java.awt.*; import java.awt.event.*; import java.io.*; import java.lang.*; import java.util.Properties; public class NoCaption { public static void main(String[] args) { frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // no title bar frame.setUndecorated(true); frame.setAlwaysOnTop( true );

Firefox Extension: Wiktionary and Google Translate

2010-10-08T13:38:00.037-04:00

Former Google Dictionary and Google Translate (As you have known, Google Dictionary site has been shut down. We try to switch to Wiktionary.org for the dictionary functionality of this extension. Since version 3.0, it is renamed to Wiktionary and Google Translate. You can install the latest version from https://addons.mozilla.org/en-US/firefox/addon/google-dictionary-and-google-t/versions/ and

Firefox Extension: YouTube Play All

2010-08-28T14:17:00.017-04:00

Note: This extension is vulnerable to changes YouTube may make to their web site or their player. It is recommended to use the YouTube Bulk Player which uses YouTube's official API and is more reliable. This extension lets you play all the YouTube video links on a page by just several clicks. Many long videos are split into small pieces and uploaded to YouTube. This help shows you how to "

Online tool: Bulk Player for YouTube

2010-08-02T14:13:00.004-04:00

Many long videos are split into small pieces and uploaded to YouTube. After you watch one part of them, you need to click on the next one to continue. But I just want to seat back and enjoy the whole video without clicking on each part separately. Bulk Player is a little online tool to let you input a bunch of URLs of the videos. When you click the Play All button, all the listed videos will

Firefox extension: Invert Input version 2

2010-07-26T19:33:00.001-04:00

Note: This is the online help of an old version. Please try the latest version. No matter what reason you want to invert your input to the browser, you can do it with this extension now. It can invert the input of a text field or a password field. After you input something into a text box, right click your mouse to pop up the context menu where

Firefox: customize the toolbar

2010-07-26T19:29:00.000-04:00

The steps to add, remove or arrange the buttons of the toolbar are 1. Right click on the toolbar. The context menu shows up. 2. Select "Customize..." from the context menu. A Customize Toolbar palette pops up. 3a. To add buttons to the toolbar, find the button from the palette and drag it to wherever you want inside the toolbar. 3b. To remove buttons from the toolbar, drag the button that you

Firefox extension programming: add an icon/button to the address bar

2010-07-22T20:29:00.000-04:00

During the development of Invert Input version 3, I tried to add an little icon to the address bar (URL bar). When the user clicked on the icon, the URL would be inverted. Although this idea was dropped, the steps of the creation of an icon in the URL bar are captured here. 1. In the overlay.xul file, added an icon to the urlbar-icons group:

Will Packed Menu (a Firefox extension) mess up your tool bar?

2010-07-21T20:48:00.000-04:00

Packed Menu was accused of corrupting the tool bar recently. I have been running this little toy since it was developed and it works great. Don't get me wrong, I am not implying that the user's comment is nonsense. I believe our users are serious about their reviews. But what could have caused the problems? Many people like to install several or many extensions on their browser. These extensions

Firefox Extension: Keylogger Beater version 2

2010-07-08T22:20:00.001-04:00

Note: This is the online help of an old version. Please try the latest version. If you are worried about keylogging programs in your system, you can try this extension. There are two different ways to input with this extension. With the help of Keylogger Beater, a keylogger running in the background can never capture what you have really input, and you will be more confident to do online

Firefox Extension: Invert Input version 1.x

2010-07-07T23:48:00.000-04:00

A scary day -- the rescue of my VirtualBox image file after upgrading Ubuntu

2010-07-07T22:59:00.000-04:00

I was using Ubuntu Hardy Heron (8.04LTS) as a guest OS on VirtualBox. The system worked excellent, but it was about time to say goodbye and upgrade it to the latest Long Term Support version Lucid Lynx (10.04LTS). I brought up a terminal, and run the command, sudo update-manager --proposed Now you see, I made a big mistake -- I had not backup-ed my data! Well, it is very easy to backup the

Install a Firefox extension for a newer/unsupported version of Firefox

2010-07-04T14:41:00.000-04:00

Some Firefox extensions are released on this site. They are free and can be downloaded from the official Mozilla Add-ons website. I would try my best to update them as soon as possible for the latest stable version of Firefox. Some users love these extensions and want to know whether I can upgrade them for the upcoming preview version of Firefox. I do not have a plan to do that yet, but that does

Firefox Extension: Keylogger Beater version 1

2010-06-27T13:27:00.000-04:00

This is the help of the old version 1. Please try the latest version. If you are worried about keylogging programs in your system, you can try this extension. There are two different ways to input with this extension. With the help of Keylogger Beater, a keylogger running in the background can never capture what you have really input, and you will be more confident to do online shopping or

gdb: skip instructions or lines while stepping the program

2010-06-16T19:13:00.001-04:00

Supposed you are at line 50 and you want to skip the following several lines of your source code and continue from line 60, you can input command jump 60 However, the command will continue your program till it meets next break

C programming: the "size" argument and return value of snprintf()

2010-06-14T23:43:00.000-04:00

Considering the following code. What would the string "s" and the return value "r" be? char s[10]; int r = snprintf(s, 3, "%d", 12345); It turns out that s would become "12" and r would be 5. Why? The second argument "size" of snprintf(char *str, size_t size, const char *format, ...) allows only up to 3 characters to be written into s. And these 3 characters includes the null terminator

VIM: go to last position when re-open a file

2010-06-02T20:13:00.000-04:00

Each time I re-open a file with vi (vim actually), the very beginning of the file is shown. If I just want to add something at the end of the file, I could quickly go to the end by pressing Shift-g. But most of the time, I need to go to where I was working on in the middle of the file. Then I have to remember some strings or phrases to search, or go down page by page. That would be a headache to

Firefox Extension: Take A Break version 1.1

2010-05-25T15:13:00.002-04:00

Click here for the online help of the old version 1.0.x. Addicted to the Web? Don't compromise your health! Continuously staring at the computer can cause headaches, blurred vision, neck pain, fatigue, dry eyes. Take A Break extension tries to help you avoid or reduce these problems. It reminds you when to take a break while you are surfing the Web. Features - A little icon on the status bar

Linux: print OS version and information

2010-05-20T18:14:00.000-04:00

The uname command prints certain system information. With the -a option, it prints all information about the Linux OS. $ uname -a The version number in the print-out is the kernel release. A Linux distribution usually has it own release versions. For example, the Ubuntu distribution may have a release version of 8.04. To see the version of a distribution, run command -- $ lsb_release -a

Firefox Extension: Keylogger Beater's More Features

2010-05-11T21:19:00.008-04:00

To know the basic usage and features of Keylogger Beater, please read this post first. Context Menu Besides Ctrl-Shift-k, you can also activate Keylogger Beater via the context menu. Right click on a text area or a password box and you can find a new menu item "Keylogger Beater". Click on it to turn on the Virtual Keyboard and start your private input. Options There are some options you

Firefox Extension: Keylogger Beater

2010-05-11T20:36:00.020-04:00

The online help of the old version 1 can be found here. The online help of the old version 2 can be found here. If you are worried about keylogging programs in your system, you can try this extension. There are two different ways to input with this extension. With the help of Keylogger Beater, a keylogger running in the background can never capture what you have really input, and you will

C++ exercise: Recursion example -- sum up numbers

2010-05-06T21:12:00.000-04:00

Q: Given a Sum and a string of numbers, add minimum operator "+" to make the sum of numbers equal to Sum. e.g. Sum=9, numbers: 101124, we get 9=1+01+1+1+2+4; Sum=88, numbers: 2112331453, we get 88=21+12+33+14+5+3. #include #include #include using namespace std; // Returns: 0 -- Got a solution. // -1 -- No solution. int Calculate(int sum, string numbers,

C++ exercises: read file with fstream and count punctuation marks

2010-05-05T20:27:00.000-04:00

Q: Write a program that reads a text file and prints a count of the number of occurrences of the punctuation marks (.,!?). #include #include #include using namespace std; int main(int argc, char *argv[]) { if (argc < 2) { cout << "Usage: " << argv[0] << " " << endl; return -1; } string s; string chs = ",.!?"; int count

C++ exercises: swap two variables

2010-05-03T21:04:00.000-04:00

Q: Swap a and b without using a third variable. Algorithm: 1. a(new) = a(old) + b(old); 2. b(new) = a(new) - b(old) = (a(old) + b(old)) - b(old) = a(old) 3. a(final) = a(new) - b(new) = (a(old) + b(old)) - a(old) = b(old) #include using namespace std; int main() { int a = 123; int b = 200; cout << "a: " << a << ", b: " << b << endl; a = a + b; cout << "a: " << a <

Online unit converter

2010-04-21T20:41:00.000-04:00

Many of the supermarkets here are playing tricks on the price tags. While the price tag displays $x.xx/lb, the receipt shows the price in dollars per kilograms. As a customer, we are always confused and hard to remember the listed price when we are reading the receipt. But why the supermarkets do that? 99 cents per pounds looks quite attractive on the price tag. People nowadays do not expect too

C++ exercises: selection sort, bubble sort, insertion sort

2010-04-20T20:31:00.001-04:00

Q: Consider the record declaration struct Month { char name[10]; //name of a month int monthnum; //number of days in the month }; a) Write a function void SortByName(Month months[], int n); that sorts an array whose

C++ exercises: exchange sort

2010-04-19T20:39:00.000-04:00

Q: Write an exchange sort function to sort the list in descending order. #include using namespace std; void ExchangeSortDesc(int a[], int sz) { if (sz < 2) return; for (int i = 0; i < sz - 1; i++) { for (int j = i + 1; j < sz; j++) { if (a[i] < a[j]) { int t = a[i]; a[i] = a[j]; a[j] = t; }

C++ exercises: tabular encrypt

2010-04-18T13:38:00.000-04:00

Q: A string of text can be encrypted using a tabular mapping that associates each letter of the alphabet with a unique letter. For example, the mapping abcdefghijklmnopqrstuvwxyz ==> ngzqtcobmuhelkpdawxfyivrsj maps "encrypt" to "tkzwsdf". Write a program that reads text until end of file and outputs the encrypted form. #include #include using namespace std; int main()

C++ exercises: Pig-latin

2010-04-17T13:35:00.001-04:00

Q: Input a series of words until end of file, converting each one to Pig-latin. If the word begins with a consonant, move the first character of the word to the last position and append "ay". If the word begins with a vowel, simply append "ay". for example, Input: this is simple Output: histay isay implesay #include #include #include

Linux: use awk to help generate XML file

2010-04-16T21:48:00.001-04:00

We have a text file product_desc.txt like this: name product1 size large weight 30lb price 10.00 quantity 100 and we want to change it into XML format: product1 large 30lb 10.00 100 So we run command: awk '{print "<"$1">"$2""}' product_desc.txt In the command, $1 refers to

C++ exercises: DaysOfWeek

2010-04-16T21:46:00.000-04:00

Q: Consider the enumerated type enum DaysOfWeek {Sun, Mon, Tues, Web, Thurs, Fri, Sat}; Write a function void GetDay(DaysOfWeek& day); that reads the name of a day from the keyboard as a string and assigns the corresponding enum value to day. Also write a function void PutDay(DaysOfWeek day) that writes the enum value to the screen. Develop a main program to test the two functions. #

C++ exercises: hex and decimal

2010-04-15T20:03:00.001-04:00

Q: Write a program that declares three integer variables i, j, k. Input a value for i in decimal and values for j and k in hex. Print all three variables in both hex and decimal. #include using namespace std; int main() { int i, j, k; cout << "input i(dec), j(hex), k(hex):"; cin >> i >> hex >> j >> k; cout << "i: " << hex << i << "(hex) " << dec << i << "(dec) " <<

C++ exercises: OctIn

2010-04-15T20:01:00.001-04:00

Q: Write a function void OctIn(unsigned int& n); that reads a base 8 (octal) number and assigns it to n. Use OctIn in a main program that reads the following octal numbers and prints the decimal equivalents: 7, 177, 127, 7776, 177777 #include using std::cin; using std::cout; using std::endl; using std::oct; void OctIn(unsigned int& n) { cin >> oct >> n; } int main() {

Add a Gadget in Blogger.com

2010-04-14T20:34:00.000-04:00

After login into Blogger.com, go to the dashboard of Blogger.com. Select "Layout" then "Page Elements". There are several places you can add a gadget. right below the title and above the posts; the side bar; the footer; It is easy to identify them because all of them have a big linked title yelling "Add a Gadget". Click on the link and you can choose the gadgets you want to add. After adding them

C++ exercises: BaseOut

2010-04-14T20:33:00.001-04:00

Q: Write a function void BaseOut(unsigned int n, int b); that outputs n in the base b, 2 <= b <= 10. Print each number in the range 2<=n<=50 in base 2, 4, 5, 8 and 9. #include using std::cout; using std::endl; void BaseOut

Firefox extension: new features of Take-A-Break

2010-04-07T20:58:00.001-04:00

New features of Take A Break are added in version 1.1 to serve the feedbacks from you. It is already submitted to the official Firefox extensions website. Please give it a try. The new features are - Sound Option You can enable sound for the short break. When it is enabled, the extension will keep beeping while the icon is flashing, and stop beeping when the short break ends. So you can know

Firefox extension programming: play sound

2010-03-30T20:45:00.000-04:00

A Firefox extension can play sound with the nsISound interface. In my next release of the extension Take A Break, I will add the sound to remind the user of a break. The interface is very easy to use. 1. Create a sound instance. sound = Components.classes["@mozilla.org/sound;1"] .createInstance(Components.interfaces.nsISound); 2. Beep. sound.beep(); That is how simple it can be

Measure the linear distance of two locations in Google Earth

2010-03-25T20:35:00.000-04:00

You can measure the linear distance of two addresses in Google Earth. There is a "Show Ruler" icon in the Toolbar of Google Earth. If you cannot see the Toolbar, you can show it by checking the "Toolbar" item under main menu "View". When you click the "Show Ruler" icon in the Toolbar, a "Ruler" dialog pops up. You can drag it aside if it blocks the view of the map. To measure a distance, click

Trim leading or trailing white spaces off a string in C++

2010-03-24T21:05:00.000-04:00

Unlike Java, there is no built-in function to remove leading or trailing white spaces from a string in C++. We can write a function to implement this. 1 void trim(string& s) 2 { 3 size_t p = s.find_first_not_of(" \t"); 4 s.erase(0, p); 5 6 p = s.find_last_not_of(" \t"); 7 if (string::npos != p) 8 s.erase(p+1); 9 } Line 1: "s" is a reference parameter

Linux: SETGID on directory

2010-03-18T20:35:00.000-04:00

SETGID stands for SET Group ID. We can use the command chmod to set the group ID bit for a directory. chmod g+s mydir or with numeric mode: chmod 2775 mydir After the change, the permission of the directory "mydir" becomes "drwxrwsr-x". drwxrwsr-x 3 zen zen 4096 2010-03-18 19:57 mydir But what is so special about setting the group ID for a directory? The trick is that when another

Firefox extension programming: add actions to status bar icon

2010-03-17T21:40:00.000-04:00

Note: This is a successive post of put an icon on the status bar. After we add our icon to the status bar of Firefox, we want to make it useful. In this tip, we show how to implement the following three functions. 1. When the mouse hovers over the icon, a tooltip pops up to show some text. 2. Clicking on the icon changes its color. 3. Right-clicking on the icon pops up a context menu.

Customize the Firefox Toolbar

2010-03-15T21:06:00.000-04:00

By default, Firefox shows Menu Bar, Navigation Toolbar, Bookmarks Toolbar at the top. They take some space and makes the view panel smaller. If you are using a netbook or a small display, you may want to customize the toolbar to hide the less used items. To do that, right click on the Menu Bar and select "Custmize..." from the context menu. A Customize Toolbar dialog pops up. You can drag and

Firefox Extension: Packed Menu

2010-03-13T08:38:00.011-05:00

Note: this extension conflicts with my another extension Packed Menu 2 Nav, which puts the button "M" on the Navigation Toolbar. If you have installed Packed Menu 2 Nav, you must uninstall it first before you install this extension. This extension adds a button "M" to the menu bar. And the original main menus are hidden. When you click the "M" button or press Alt-M, the original main menus are

Convert string to number in C++

2010-03-11T20:35:00.000-05:00

There are several methods to convert a string to number in C++. We use floating point numbers as examples. There are similar functions for integer. Method 1: use function atof(). The syntax of atof() is: #include double atof(const char *nptr); The conversion code could be: const char *a = "234.5"; double d; d = atof(a); There is a little problem with this function. It

Firefox extension programming: put an icon on the status bar

2010-03-10T20:15:00.003-05:00

To better understand this article, you should have the basic knowledge of building a Firefox extension. You can refer to my another post Learn how to create a Firefox extension in 10 minutes if needed. To put an icon on the status bar of Firefox, we first need to "overlay" the status bar in our main *.xul file. Let us name it "overlay.xul":

Change the secret configuration parameters of Mozilla Firefox/Thunderbird

2010-03-05T20:27:00.001-05:00

There are many secret parameters you can use to tweak your Mozilla Firefox or Thunderbird. It is different to access them between Firefox and Thunderbird. In Firefox, input "about:config" in the address box. Firefox will warn you: "This might void your warranty!". It IS dangerous if you mess up with the parameters. But if you are confident, just click the "I'll be careful, I promise!" button to

Slow SSH connection to remote server

2010-03-04T19:57:00.000-05:00

When I tried to ssh connect to a new remote server, it took a longer time. Although it got connected finally. I was curious so I turned on the debug mode: ssh -v remote_server The log showed that there was a pause when ssh client application was trying authentication method gssapi-with-mic. After 3 trials, ssh client tried the next authentication method and succeeded: debug1:

Check out Java project from CVS to Eclipse

2010-02-26T19:55:00.000-05:00

Step 1: Start Eclipse. Select menu "File|Import...". Step 2: The "Import" dialog pops up. Select "CVS|Projects from CVS". Click "Next". Step 3: Select "Create a new repository location". Click "Next" to add the CVS repository location. orSelect "Use existing repository location:". Select the wanted repository location from the list. Click "Next". Step 4: Select "Use an existing module (this

How to change the options/preferences of a Mozilla Firefox/Thunderbird extension

2010-02-25T21:07:00.000-05:00

Most of the extensions of Mozilla Firefox or Mozilla Thunderbird have "Options" dialogs. To open the "Options" dialog, you can: Step 1: click the "Tools" button in the menu bar; Step 2: select the "Add-ons" item; Step 3: select the "Extensions" icon; Step 4: select the extension you want and the "Options" button will show up; Step 5: click the "Options" to open the dialog.

Detect memory allocation failure in C++

2010-02-24T19:23:00.000-05:00

In C++, we use "new" to allocate a piece of memory. There are chances that the allocation may fail. Upon the failure of allocating memory, the developer may want to do some clean-up or logging. You may see this piece of code in some old programs: char *p = new char[buffer_size]; if (!p) { // error handling ... } It worked in the last century, but not any more. The problem of this piece of code

Porting Firefox extension to Thunderbird

2010-02-23T20:38:00.000-05:00

After I published the Autohide Tabbar Firefox extension, some positive comments were received. Thank you! It encourages me to keep improving it. One of the comments was asking whether the Autohide Tabbar extension could be added to Mozilla Thunderbird. I looked into Thunderbird and found out that since version 3, tabs were introduced. After some more investigations, it was discovered that porting

JavaScript: trim leading or trailing spaces from a string

2010-02-19T19:34:00.001-05:00

There is no built-in function to remove leading or trailing spaces from a string in JavaScript. To do that, we can use the replace() method of the String object. The syntax of String's replace() method is: string.replace(regexp/substr,newstring); The first parameter can be a regular expression. The second parameter is a new string to replace what the regular expression matches in the string. So

GNU C++ compiler (g++) does not like the typical hello-world program

2010-02-18T17:54:00.000-05:00

In some old text books or web sites, you can see the standard or traditional "hello world" program like this: #include main() { cout << "Hello World!" << endl; } If you use the latest GNU C++ compiler to build this program, you will get a warning. $ g++ helloworld.cpp In file included from /usr/include/c++/4.2/backward/iostream.h:31, from helloworld.cpp:1: /usr/

Linux: EADDRNOTAVAIL (Address not available) error

2010-02-07T19:39:00.001-05:00

If you are running many TCP client programs on your machine and these programs do not specify ports when they make connections to the server, the system would assign temporary ports for them. When a connection is closed, the port will be returned to the system for reuse. The temporary ports have a limited range. When the allowed connections are exhausted, the program could get an error when it

Firefox Extension: Invert Input

2010-02-05T19:42:00.010-05:00

Note: Online help of the old version 1 can be found here. Note: Online help of the old version 2 can be found here. No matter what reason you want to invert your input to the browser, you can do it with this extension now. It can invert the input of a text field or a password field. Overview This extension auto-hides your Firefox/Thunderbird's tab bar. It can also relocate the tab bar to the bottom of the browser window. It supports Thunderbird since version 2.0.

Google Chrome Extension: Take A Break

2010-01-10T16:06:00.007-05:00

Addicted to the Web? Don't compromise your health! Continuously staring at the computer can cause headaches, blurred vision, neck pain, fatigue, dry eyes. Take A Break extension tries to help you avoid or reduce these problems. It reminds you when to take a break while you are surfing the Web. Features - A little icon on the tool bar will be flashing every 15 minutes to remind you a short break.

Google Chrome: content script limitations make my extension look bad

2010-01-05T19:03:00.004-05:00

After I published my Google Chrome extension Boss Key and Button, some positive feedbacks were received in the beginning. But later on, I kept receiving comments saying that the the extension was not working. That puzzled me for quite some time because I had developed it in a quite early version of Google Chrome (the dev channel) and tested it on both Windows and Linux successfully.