In pseudocode this goes like this:

<if this evaluates to TRUE> then <parse this> else <parse this>

All you need to do is replace the "then" with a question mark and the "else" with a colon:

<if this evaluates to TRUE> ? <parse this> : <parse this>

For example:

print  $trueOrFalse ? "you're telling the truth" : "you're lying";

Ignore the print command, it's not part of the if/then/else statement, it's just here to do something with the outcome of that statement.

The expression immediately to the left of the question mark is evaluated. The expression between the question mark and the colon is parsed if the expression evaluates to TRUE, otherwise the expression immediately to the right of the colon is parsed. So in the above example, either "you're telling the truth" or "you're lying" is printed, depending on whether $trueOrFalse is ... you guessed it ... TRUE or FALSE.

But perhaps a more common situation is toggling the value assigned to a variable. For example, toggling between TRUE and FALSE:

$trueOrFalse = $trueOrFalse ? FALSE : TRUE;

Here's a practical example of the use of if/then/else one liners. There's two in this chunk of PHP. The scroll box list below the code is the kind of thing this PHP produces.

<div style="overflow:auto; height:100px; width:300px; border:3px groove #DDD; padding:0">
<?php
    $alternateLine = FALSE;
    while($presidentsArray) {
        print "<div style=\"background-color:";
        print $alternateLine ? "#F5F8F9" : "white";
        print "; padding-bottom: 1px\"> &nbsp; &nbsp; <a href=\"someURL\" title=\"This link goes nowhere\">" .
          $presidentsArray['name'] . "</a></div>";
        $alternateLine = $alternateLine ? FALSE : TRUE;
    }
?>
</div>

So I was delighted to hear Jeff Atwood and Joel Spolsky’s views on the Stack Overflow Podcast #45:

Atwood:   … programmers love hierarchy, to a degree that they don't even understand how different they are than the public in this regard. Like they love putting everything in this little bucket, that goes in this little bucket, which is this sub-bucket of this and this, and normal people hate that. And threading is totally a manifestation of that and it drives me crazy that a lot of programmers can't see that they're like immediately like: "Oh, threading is good. I love threading. What are you talking about?" You know? They can't see it at all.

Spolsky:   Right, right.

Atwood:   It's like myopia.

Spolsky:   Yeh. I mean it's really a function of the size of the group, and one thing I've learned through years and years of usability testing is that anything that smacks of a hierarchy or a tree is not going to be understandable to the average, non-technical user.

Atwood:   Yeh.

Spolsky:   You just have to learn that: if it's a tree, or a hierarchy, like eighty per cent of the regular people are going to get confused and not quite get it.

Hierarchies are great at showing nested relationships, and they make sense to programmers, who are used to them – but most of the time the relationships don’t matter to the user. Usually the user just wants to find something and yet the tree view forces them to “drill down”, clicking down into a hierarchy that becomes increasingly complex as they click.

My request to all programmers placed in the position of having to design a user interface: avoid hierarchies unless you truly believe the end users really need the hierarchical information.

Have a listen to Hanselminutes Show 134 to hear Jeff Atwood, CEO of Stack Overflow, talking about the concept of the site and what they’ve done to make it an appealing place for software developers to hang out. The bit that really struck a chord with me was when he described Stack Overflow as sort of an antidote to Experts’ Exchange, the latter being a site that really rubs me up the wrong way because of its underhand tactics. There are so many times I’ve searched for something technical on Google and found a hit that looks like it might provide the answer I was looking for but I don’t notice it’s at Experts’ Exchange until I get there and discover the details are obscured because the site is run as a private club, which I refuse to join.

I like Stack Overflow. The only thing I don’t like about it is that I think its search facility is very weak right now. If you want to find stuff it’s best to use Google, like this:

http://www.google.com/search?q=site:stackoverflow.com/questions YOUR QUERY

For example:

http://www.google.com/search?q=site:stackoverflow.com/questions online help

The other aspect of it is that, if you’re not a programmer – or even if you are – it can be an intimidating place for the newcomer. You have to brace yourself and be prepared to be told you’re an idiot and should go away and never darken the doors of Stack Overflow again. But, in some ways, that’s not altogether a bad thing. It’s intended to be a games room for professional programmers – it’s not designed for just anybody to go and find an answer to any old thing. But, unlike Experts’ Exchange, everyone’s allowed to come in and wander around and listen in on the conversations. However, if you try answering a question you’re not qualified to answer, or you start asking questions that should have been asked elsewhere, then you can expect the regulars to give you a hard time.

This isn’t a Photoshop job, it’s a real error message, presumably tucked away in some remote corner of Microsoft Word.

Update:

Turns out it's nothing to do with Word (more's the pity). It's a "feature" of Notepad++, which is my text editor of choice right now. I must have been closing down Notepad++ at the same time as Word.

• Customer The process is centred around the customer. It's not about producing some new, cool product because it's something we think would be interesting to work on, or because it's this year's big thing. It's about finding out what our customers and potential customers need and value and doing that for them.
• Demonstrations Show your customers the real production software (not a prototype or a smoke and mirrors job) on a regular basis and get their feedback.
• Iterative Build something, demo it, get feedback, build some more, and so on. Demonstrations could be a week or a month apart, but probably not more than a month apart, and always on a regular schedule. Don't go away and work on something for six months or a year only to find at the end of that time that it's not really what the customer wants, because they found it hard to explain, or you weren't listening, or they changed their minds/personnel, or the market or operational environment changed.
• Collaborative This isn't the waterfall approach. There's no leader passing down commands that must be obeyed. Within the company everyone's got a role and a job to do, but these aren't set in stone with high walls. The team have to work together according to their knowledge and abilities to get the job done. And, looking externally, you've got to collaborate with the customer and bring them into the process.

Take a look at the Quick Start screencast from fiddlertool.com:
 
This video is hosted at: http://www.fiddlertool.com/Fiddler/firstrun.asp

For example, say you have a table containing Web links to a server on your network and the server name gets changed or, more likely, the Web pages get moved. You might have links such as http://oldwebserver/importantstuff/index.html that should now be http://newwebserver/importantstuff/index.html.  To correct these with an SQL statement, use:

UPDATE table_name SET field_name = REPLACE (
field_name,
"old text",
"new text");

For example:

UPDATE mytable SET url = REPLACE (
url,
"http://oldwebserver/importantstuff/",
"http://newwebserver/importantstuff/");

Note: The reason I didn't just replace "oldwebserver" with "newwebserver" is as a safeguard against changing things I didn't want changed. You've got to be pretty careful about what you do, and I would strongly advise that you always back up the database before making any changes like this.

WordPress expert Lorelle has some good advice about doing this kind of thing on your WordPress tables at:

http://lorelle.wordpress.com/2005/12/01/search-and-replace-in-wordpress-mysql-database/

If, however, you get a blank page, it suggests the Web server knows that .php files should be served up like Web pages, but the PHP isn't being handled properly.

On Apache, the most likely cause - or at least the first thing you should check out - is that the httpd.conf file hasn't been updated properly to point to the PHP module. Make sure this file contains LoadModule, AddType and PHPIniDir statements such as the following (these are for an XAMPP installation of Apache/PHP on Windows):

LoadModule php5_module "c:/xampp/php/php5apache2_2.dll"
AddType application/x-httpd-php .php
PHPIniDir "c:/xampp/php"

If these lines are in the httpd.conf file, the problem may just be that the file hasn't been read since the change was made. Restart Apache and the changes in the file will be applied.

The idea is that you add in a selection of questions/answers (e.g. words/phrases in German and their English meanings, or questions about car engine parts and the answers to those questions), then you just test yourself by going through a few questions every now and again and checking the answers if you need to. I have the program set as a scheduled task so that it pops up every couple of hours and I can do a few questions, or just click Quit. The questions are randomly selected, so you get different ones coming up each time.

The installer I've put up for download comes with a default French/English data file. This presents French words/phrases. You've got to remember the English meanings. Click Next to page through from one French word/phrase to the next:

You can click English if you can't remember the word/phrase.

To add or remove  entries to/from the data file, click Feed.
 
Scroll to the bottom and add more French words and their English meanings, or click in the left, grey column to highlight a row and press Delete on the keyboard to remove it. To get rid of everything and add your own data, highlight the lot and press Delete. The Properties tab allows you to change the button text from French/English to something that suits your questions/answers.

See the Downloads page for a link to the Memory Builder installer.

Adapted from a Dummies article: Determining Types of Numbers in C