The common way is to write constructors like methods and simply omit the return type.

![enter image description here][1]

If you want to be extra clear, you can add `&lt;&lt;constructor&gt;&gt;` in front.


  [1]: http://i.stack.imgur.com/k0z2v.jpg

Is there some function which will tell me how many bytes does a string occupy in memory?

I need to set a size of a socket buffer in order to transfer the whole string at once.

How many bytes does a string have

I&#39;m trying to use php to create a zip file (which it does - taken from this page - http://davidwalsh.name/create-zip-php), however inside the zip file are all of the folder names to the file itself. 

Is it possible to just have the file inside the zip minus all the folders?

Here&#39;s my code:

    function create_zip($files = array(), $destination = &#39;&#39;, $overwrite = true) {
        
        if(file_exists($destination) &amp;&amp; !$overwrite) { return false; };
        $valid_files = array();
        if(is_array($files)) {
            foreach($files as $file) { 
                if(file_exists($file)) { 
                    $valid_files[] = $file;
                };
            };
        };
        if(count($valid_files)) { 
            $zip = new ZipArchive();
            if($zip-&gt;open($destination,$overwrite ? ZIPARCHIVE::OVERWRITE : ZIPARCHIVE::CREATE) !== true) { 
                return false;
            };
            foreach($valid_files as $file) { 
                $zip-&gt;addFile($file,$file);
            };
            $zip-&gt;close();
            return file_exists($destination);
        } else {
            return false;
        };
        
    };
    
    
    $files_to_zip = array(&#39;/media/138/file_01.jpg&#39;,&#39;/media/138/file_01.jpg&#39;,&#39;/media/138/file_01.jpg&#39;);
    
    $result = create_zip($files_to_zip,&#39;/...full_site_path.../downloads/138/138_files.zip&#39;);



php creating zips without path to files inside the zip

I am a complete ROOKIE at this so I need some help on it.

How would you create uml class diagram and constructors with parameters.

for default (no parameters) you do

policyholder() for diagram and pseudo-code

for parameters would you do the same thing

policyholder (policynumber, service class, and customer age) for class diagrams and pseudo-code.

It also asked to initialize each attribute to value where an object of this type can be instantiated, If a policy number is not between 1000 and 999 inclusive, then set the policy number to 0. (policy number is attribute)



uml classdiagram constructor with parameters

I am a complete ROOKIE at this so I need some help on it.
How would you create uml class diagram and constructors with parameters.
for default (no parameters) you do
policyholder() for diagram and pseudo-code
for parameters would you do the same thing
policyholder (policynumber, service class, and customer age) for class diagrams and pseudo-code.
It also asked to initialize each attribute to value where an object of this type can be instantiated, If a policy number is not between 1000 and 999 inclusive, then set the policy number to 0. (policy number is attribute)

I&#39;m new to JavaScript. New as far as all I&#39;ve really done with it is tweaked existing code and wrote small bits of jQuery.

Now I&#39;m attempting to write a &quot;class&quot; with attributes and methods, but I&#39;m having trouble with the methods. My code: 


    
    function Request(destination, stay_open) {
        this.state = &quot;ready&quot;;
        this.xhr = null;
        this.destination = destination;
        this.stay_open = stay_open;
		
        this.open = function(data) {
            this.xhr = $.ajax({
                url: destination,
                success: this.handle_response,
                error: this.handle_failure,
                timeout: 100000000,
                data: data,
                dataType: &#39;json&#39;,
            });
        };
	
        /* snip... */

    }

    Request.prototype.start = function() {
        if( this.stay_open == true ) {
            this.open({msg: &#39;listen&#39;});
        } else {
    
        }
    };
    //all console.log&#39;s omitted

The problem is, in `Request.prototype.start`, `this` is undefined and thus the if statement evaluates to false. What am I doing wrong here? 

&#39;this&#39; is undefined in JavaScript class methods

Why does the following class declaration inherit from `object`?

    class MyClass(object):
        ...

Why do Python classes inherit object?

I have a class that contains only fields and no methods, like this:


    class Request(object):
        
        def __init__(self, environ):
            self.environ = environ
            self.request_method = environ.get(&#39;REQUEST_METHOD&#39;, None)
            self.url_scheme = environ.get(&#39;wsgi.url_scheme&#39;, None)
            self.request_uri = wsgiref.util.request_uri(environ)
            self.path = environ.get(&#39;PATH_INFO&#39;, None)
            # ...

This could easily be translated to a dict. The class is more flexible for future additions and could be fast with `__slots__`. So would there be a benefit of using a dict instead? Would a dict be faster than a class? And faster than a class with slots?


Should I use a class or dictionary?

Is there a difference between

    class A:
        ...

and

    class A():
        ...

I just realized that a couple of my classes are defined as the former and they work just fine. Do the empty parenthesis make any difference?

Python class definition syntax

**How do I dynamically define a class in Ruby WITH a name?**

I know how to create a class dynamically **without** a name using something like:

    dynamic_class = Class.new do
      def method1
      end
    end

But you can&#39;t specify a class name. I want to create a class dynamically **with** a name. 

Here&#39;s an example of what I want to do but of course it doesn&#39;t actually work.  
(Note that I am not creating an instance of a class but a class definition)

    class TestEval
      def method1
        puts &quot;name: #{self.name}&quot;
      end
    end

    class_name = &quot;TestEval&quot;
    dummy = eval(&quot;#{class_name}&quot;)

    puts &quot;dummy: #{dummy}&quot;

    dynamic_name = &quot;TestEval2&quot;
    class_string = &quot;&quot;&quot;
    class #{dynamic_name}
      def method1
      end
    end
    &quot;&quot;&quot;
    dummy2 = eval(class_string)
    puts &quot;dummy2: #{dummy2}&quot; # doesn&#39;t work


Actual output:  

    dummy: TestEval
    dummy2: 

Desired output:

    dummy: TestEval
    dummy2: TestEval2


======================================================

**Answer: A totally dynamic solution using sepp2k&#39;s method**

    dynamic_name = &quot;TestEval2&quot;

    Object.const_set(dynamic_name, Class.new) # If inheriting, use Class.new( superclass )
    dummy2 = eval(&quot;#{dynamic_name}&quot;)
    puts &quot;dummy2: #{dummy2}&quot;



Dynamic Class Definition WITH a Class Name

Consider:

    struct mystruct_A
    {
       char a;
       int b;
       char c;
    } x;

    struct mystruct_B
    {
       int b;
       char a;
    } y;

The sizes of the structures are 12 and 8 respectively.

Are these structures padded or packed?

When does padding or packing take place?


Structure padding and packing

In my project I need to know what a `zlib` header looks like. I&#39;ve heard it&#39;s rather simple but I cannot find any description of the zlib header.

For example, does it contain a magic number?


What does a zlib header look like?

It seems to me that C&#39;s arrow operator (-&gt;) is unnecessary. The dot operator (.) should be sufficient. Take the following code:

    typedef struct {
        int member;
    } my_type;

    my_type   foo;
    my_type * bar;
    int       val;

    val = foo.member;
    val = bar-&gt;member;

We see that the arrow operator must be used to dereference bar. However, I would prefer to write

    val = bar.member;

There is no ambiguity as to whether I am trying to pull &#39;member&#39; from a structure or from a pointer to the structure. But it is easy to use the wrong operator, especially when refactoring code. (For example, maybe I am doing some complex operations on foo, so I move the code into a new function and pass a pointer to foo). I don&#39;t think I need to care whether foo is a pointer or not; the compiler can worry about the details.

So the question: wouldn&#39;t it be simpler to eliminate -&gt; from the C language?

Arrow Operator vs. Dot Operator

I started populating an en yaml file in Rails and I can already tell it will get messy and out of hand before too long. Is there a convention to keeping this file organized?

So far I have this structure:

    language:
      resource:
        pages: # index, show, new, edit
          page html elements: # h1, title
      activerecord:
        attributes:
          model:
            property:

Now I have the following things that I want to fit into this structure but I&#39;m unsure how to:

 1. Navigation
 2. Button text (save changes, create account, etc)
 3. Error messages from controller flash
 4. How to add multi-word keys. Do I use a space or an underscore? For exmaple, `t(&quot;.update button&quot;)`) or `t(&quot;.update_button&quot;)`

Is there a convention to locale file structure?

How do you structure i18n yaml files in Rails?

I am trying to convert some C++ code to C and I am facing some problems.
How can I define inside a structure a function?

Like this:

     typedef struct  {
	    double x, y, z;
	    struct Point *next;
	    struct Point *prev;
	    void act() {sth. to do here};
    } Point;

Can I define a function inside a C structure?

I&#39;m searching a way to represent my Django project model graphically.

Is there a &quot;native&quot; way to do this kind of [ERD][1] (diagram) ?

---

Update following [@Etienne instructions](https://stackoverflow.com/a/6777376/305189)

Here is an example of how I finally view the PDF representing some models of my django project

    $ python manage.py graph_models app1 app2 ... | dot -Tpdf | evince

- It actually generates the dot data with my applications (app1, app2, ...)
- Passes the result to `dot` to output into PDF format
- Opens the output with `evince`

  [1]: http://en.wikipedia.org/wiki/Entity-relationship_model

Django - Model graphic representation (ERD)

I am trying to visualize my data flow with a Sankey Diagram in R.

I found [this blog post](http://biologicalposteriors.blogspot.com/2010/07/sankey-diagrams-in-r.html) linking to an R script that produces a Sankey Diagram; unfortunately, it&#39;s quite raw and somewhat limited (see below for sample code and data).

Does anyone know of other scripts—or maybe even a package—that is more developed? My end goal is to visualize both data flow and percentages by relative size of diagram components, like in [these  examples of Sankey Diagrams](http://www.sankey-diagrams.com/tag/software/). 

I posted [a somewhat similar question on the r-help list](http://tolstoy.newcastle.edu.au/R/e17/help/12/03/7682.html), but after two weeks without any responses I&#39;m trying my luck here on stackoverflow.

Thanks,
Eric

PS. I&#39;m aware of the [Parallel Sets Plot](https://stats.stackexchange.com/questions/12029/is-it-possible-to-create-parallel-sets-plot-using-r), but that is not what I&#39;m looking for.

    # thanks to, https://tonybreyal.wordpress.com/2011/11/24/source_https-sourcing-an-r-script-from-github/
      sourc.https     &lt;- function(url, ...) {
    # install and load the RCurl package 
    if (match(&#39;RCurl&#39;, nomatch=0, installed.packages()[,1])==0) {
      install.packages(c(&quot;RCurl&quot;), dependencies = TRUE)
      require(RCurl)  
    } else require(RCurl)    

    # parse and evaluate each .R script
      sapply(c(url, ...), function(u) {
        eval(parse(text = getURL(u, followlocation = TRUE, 
        cainfo  = system.file(&quot;CurlSSL&quot;, &quot;cacert.pem&quot;, 
        package = &quot;RCurl&quot;))), envir = .GlobalEnv)
     } )
     }
    
    # from https://gist.github.com/1423501
    sourc.https(&quot;https://raw.github.com/gist/1423501/55b3c6f11e4918cb6264492528b1ad01c429e581/Sankey.R&quot;)
    
    # My example (there is another example inside Sankey.R):
    inputs = c(6, 144)
    losses = c(6,47,14,7, 7, 35, 34)
    unit = &quot;n =&quot;
    
    labels = c(&quot;Transfers&quot;,
               &quot;Referrals\n&quot;,
               &quot;Unable to Engage&quot;,
               &quot;Consultation only&quot;,
               &quot;Did not complete the intake&quot;,
               &quot;Did not engage in Treatment&quot;,
               &quot;Discontinued Mid-Treatment&quot;,
               &quot;Completed Treatment&quot;,
               &quot;Active in \nTreatment&quot;)
    
    SankeyR(inputs,losses,unit,labels)
    
    # Clean up my mess
    rm(&quot;inputs&quot;, &quot;labels&quot;, &quot;losses&quot;, &quot;SankeyR&quot;, &quot;sourc.https&quot;, &quot;unit&quot;)

Sankey Diagram produced with the above code, ![Sankey Diagram produced with the code above][1]

  [1]: http://i.stack.imgur.com/9jiMq.png

Sankey Diagrams in R?

Is there a simple online tool that will generate a dependency graph (boxes linked by arrow lines) based on text input like: 

A -&gt; B

Much like this one:

[www.websequencediagrams.com][1]

(It generates a sequence diagram)


  [1]: http://www.websequencediagrams.com

How to generate dependency graph with text

My kids have this fun game called [Spot It!][1] The game constraints (as best I can describe) are:

 - It is a deck of 55 cards
 - On each card are 8 unique pictures (i.e. a card can&#39;t have 2 of the same picture)
 - **Given any 2 cards chosen from the deck, there is 1 and only 1 matching picture**. 
 - Matching pictures may be scaled differently on different cards but that is only to make the game harder (i.e. a small tree still matches a larger tree)

The principle of the game is: flip over 2 cards and whoever first picks the matching picture gets a point. 

Here&#39;s a picture for clarification:

![spot it][2]

(Example: you can see from the bottom 2 cards above that the matching picture is the green dinosaur. Between the bottom-right and middle-right picture, it&#39;s a clown&#39;s head.)

I&#39;m trying to understand the following: 

1. What are the minimum number of different pictures required to meet these criteria and how would you determine this? 

2. Using pseudocode (or Ruby), how would you generate 55 game cards from an array of N pictures (where N is the minimum number from question 1)? 

**Update:**

Pictures do occur more than twice per deck (contrary to what some have surmised). See this picture of 3 cards, each with a lightning bolt:![3 cards][3]


  [1]: http://www.blueorangegames.com/spotit-tg.php
  [2]: http://i.stack.imgur.com/Lv4I1.jpg
  [3]: http://i.stack.imgur.com/9Pk2v.jpg

What are the mathematical/computational principles behind this game?

I have two rectangles characterized by 4 values each : 

Left position `X`, top position `Y`, width `W` and height `H`:

    X1, Y1, H1, W1
    X2, Y2, H2, W2

Rectangles are not rotated, like so:

    +--------------------&gt; X axis
    |
    |    (X,Y)      (X+W, Y)
    |    +--------------+
    |    |              |
    |    |              |
    |    |              |
    |    +--------------+
    v    (X, Y+H)     (X+W,Y+H)
    
    Y axis

What is the best solution to determine whether the intersection of the two rectangles is empty or not?

Two Rectangles intersection

    Program A()
    {
    	x, y, z: integer;
    
    	procedure B()
    	{
    		y: integer;
    		y=0;
    		x=z+1;
    		z=y+2;
    	}
    
    	procedure C()
    	{
    		z: integer;
    
    		procedure D()
    		{
    			x: integer;
    			x = z + 1;
    			y = x + 1;
    			call B();
    		}
    
    		z = 5;
    		call D();
    	}
    
    	x = 10;
    	y = 11;
    	z = 12;
    	call C();
    	print x, y, z;
    }

From my understanding, the result of this program when run using **static scoping** is: x=13, y=7, and z=2.

However, when it is run using **dynamic scoping**, the result is: x=10, y=7, and z=12.

These results are the ones that our professor gave us. However, I cannot understand for the life of me how he has reached these results. Could someone possibly walk through the pseudocode and explain their values in the two different types of scopes?

Content Type	Original Author	Original Content on Stackoverflow
Question	blake	View Question on Stackoverflow
Solution 1 - Class	magnattic	View Answer on Stackoverflow

uml classdiagram constructor with parameters

Class Problem Overview

Class Solutions

Solution 1 - Class

php creating zips without path to files inside the zip

How many bytes does a string have

Attributions