Is there some way to call a class which is defined by String or a similar way? I have a program where, if the user enters "1" then the "Assignment01" class will be called and if the user enters "14" then the "Assignment14" class will be called and so on.  Currently, I am using Switch Case Statement to call a function according to the user's number input like shown on the code. But what if there were 100 of classes which needs to be called per the user's input?  It will be really frustrating to have to create a case for calling every single class. So, is there another way to make it short and efficient?  For example:  // Assume user inputs "10" so 'userInput = 10' String classVariable = "Assignment" + userInput + ".main(args)";  classVariable; // Result in like 'Assignment10.main(args);'   Unfortunately, this can't be done as that is a String but is there a similar way like to define that String into a class so it can be called like that?  EDIT: All I want is that when the user enters integer like say "30" then the class "Assignment30" should be called which can be done like "Assignment30.main(args);" through a switch case statement but I can't create every single case.  It would be better if I could put like say "Assignment+userInput+.main(args);" or something.  CODE:-  switch (userInput) {      default:         AssignmentMain.errorLevel();         break;      case 1:         System.out.println();         Assignment01.main(args);         break;       case 2:         System.out.println();         Assignment02.main(args);         break;      case 3:         System.out.println();         Assignment03.main(args);         break;      case 4:         System.out.println();         Assignment04.main(args);         break;      case 5:         System.out.println();         Assignment05.main(args);         break;  }
What is reflection and why is it useful? What is reflection, and why is it useful?  I'm particularly interested in Java, but I assume the principles are the same in any language.
var self = this? Using instance methods as callbacks for event handlers changes the scope of this from "My instance" to "Whatever just called the callback". So my code looks like this  function MyObject() {   this.doSomething = function() {     ...   }    var self = this   $('#foobar').bind('click', function(){     self.doSomethng()     // this.doSomething() would not work here   }) }   It works, but is that the best way to do it? It looks strange to me. Why is glass transparent? Once I asked this question from my teacher and he replied "Because it passes light.". "And why does it pass light?" I asked and he said, "Because it is transparent.".  The same question again, Why glass is transparent? Why does light pass through it, while for opaque objects, it does not? Family of irreducible polynomials I'm trying to search and replace a string in all files matched by grep: grep -n 'foo' * will give me output in the form: [filename]:[line number]:[text]  For each file returned by grep, I'd like to modify the file by replacing foo with bar. How to obtain the sum of the following series? $\sum_{n=1}^\infty{\frac{n^2}{2^n}}$ When do we still need the table and figure environments when we don't want the enclosed objects to float? The LaTeX Wikibook :     Please understand: you do not have to use floating tables. It only   looks more professional. If you want to place your tables where they   lie in your source code, do not use table at all! This is a very   common misunderstanding among newcomers.   LaTeX works with an intricate , but I often prefer immediate placement with the H placement specifier (enabled by the float package).  My understanding is that captions and table/figure numbering require the table/figure environments. Is this really so, or are there ways around that? What other reasons are there for using table/figure if we know that we don't want a particular object to float? Using [Authorize] without SimpleMembershipProvider Is it possible to save settings for Microsoft Paint? After closing paint the last used settings went back to default. I want them to be saved. Like the selected Brush-Tool, Color, Line-strength, etc.  Either after every usage or I define one I use most. Maybe through the registry or by start parameters? Why the number of indexed pages decreased for a "site:" search Recently I created a website with hundreds of thousands of unique pages. A week ago, Google had indexed about 250,000 pages. It has now decreased to 90k URLs (using a site:domain.com query).   What should I do to have Google index all the pages again? Why did all these pages get de-indexed from Google?. Where can I find every gnome? I am trying to align some text to left/center/right in the same line. For example, I want to put my phone number on the left, my name in the center, and my email on the right, how do I do that? Why is there no overload of Interlocked.Add that accepts Doubles as parameters? wp_customize_image_control default value I am trying to create a custom theme using Wordpress 3.4's customization options. I would like to create an option to change the theme's logo, but I would like to also display a default logo image.   I am using the following code in my function.php page:  $defaultbranding = "get_bloginfo('template_directory') . '/images/logo.png";      $wp_customize-&gt;add_setting( 'change_branding', array(         'default' =&gt; get_bloginfo('template_directory') . '/images/logo.png',     ) );      $wp_customize-&gt;add_control( new WP_Customize_Image_Control( $wp_customize, 'change_branding', array(         'label'   =&gt; 'Image Control',         'section' =&gt; 'theme_settings',         'settings'   =&gt; 'change_branding',     ) ) );   And in the theme's header.php page:  src='&lt;?php echo get_theme_mod( 'change_branding' , 'default' ) ?&gt;'   I would like the 'default' value on the front end to be:  get_bloginfo('template_directory') . '/images/logo.png'   Is there some way I can achieve this?  Thanks in advance for any help. Flag indicator present on Meta, but no flags visible Unwanted behaviour from dict.fromkeys What does the word treats mean in this context? I don't think it means entertainment, food, drink etc.. Maybe it is an old usage of this word? Does it mean influencing factors or something like that?  This is the first part of the title of the first chapter of the novel "Oliver Twist" by Charles Dickens. The whole title reads:     Treats of the Place Where Oliver Twist was Born and of the Circumstances Attending His Birth Is there a way to make PythonTEX compile as of today in Overleaf V2 ?  \documentclass[]{article} \usepackage[utf8]{inputenc} \usepackage{pythontex}  \begin{document} \begin{pyverbatim} def calc_ellipticity(theta, delta):     theta = np.deg2rad(theta)     psi = np.arcsin(np.sin(2*theta) * np.sin(delta))/2     return np.tan(psi) \end{pyverbatim} \end{document}   Compiling gives : ? PythonTEX ? Lowest voltage drop diode possible I am harvesting energy from an NFC device using a tuned antenna on my PCB. Though this method I am able to generate about 3.05V. I would like to charge a super capacitor using the power harvested from the NFC device. To do this I have  used the simple diode circuit provided  (and shown in Figure 1 below).  The problem I am facing is my circuit requires a minimum of 3V to operate within operating conditions, however with the added drop by typical diodes I believe there with be various situations where the generated voltage will drop below the required 3V. Are there any Diodes available which have ultra low voltage drops of less then 0.01V? and is that even possible?  Please note:   my system load will be &lt; 5mA  The 3.05V generated was without a diode in the circuit Sum of digits of repunits Find a polynomial f(x) of degree 5 such that 2 properties hold. I have been trying to find a polynomial $f(x)$ such that these $2$ properties hold:   $f(x)-1$ is divisible by $(x-1)^3$ $f(x)$ is divisible by $x^3$   To start, I set $f(x) =ax^5 + bx^4 + cx^3 + dx^2 + ex + f$. This is divisible by $x^3$, so $d, e, f $  must be $0$. So polynomial $f(x) = ax^5 + bx^4 + cx^3$  This minus $1$ is divisible by $(x-1)^3$. So I used synthetic division and got that the remainder of $ax^5 + bx^4 + cx^3$ divided by $(x-1)$ is $a+b+c-1$. But it should divide out evenly, so $a+b+c-1 = 0$.  From here, I can't find any other equations involving the three variables. Could someone have any suggestions for how to continue? Thanks in advance. :)