From :     Object interfaces allow you to create code which specifies which methods    a class must implement, without having to define how these methods are handled.   Why should I need to do that? Could it be a kind of 'documentation'?  When I'm thinking about a class I have to implement, I know exactly which methods I should code.  What are some situations where interfacing a class is a "best practice"?
allow you to create code which defines the methods of classes that implement it. You cannot however add any code to those methods.    allow you to do the same thing, along with adding code to the method.   Now if you can achieve the same goal with abstract classes, why do we even need the concept of interfaces?   I've been told that it has to do with OO theory from C++ to Java, which is what PHP's OO stuff is based on. Is the concept useful in Java but not in PHP? Is it just a way to keep from having placeholders littered in the abstract class? Am I missing something?
Developer Accounts for ExactTarget Why do the less than symbol () appear wrong as upside down exclamation (¡) or question mark (¿)? When typing &lt; or &gt; in LaTeX and compiling with pdflatex, the less than and greater than symbols appear at upside down exclamation points. I'm not in math mode. I'm trying to model my face on Blender using  and it gives links to reference photos.  The thing is, as I mentioned above, I want to try and model my face.  So I've decided to take photos of my face. But it doesn't seem to be working well (not symmetrical enough and stuff), so how exactly should I take my reference photos so that it would work well when I try to model it with the Mirror modifier?  Note: I only have the 'webcam' on my Macbook Pro and the camera on my Hongmi phone and I don't want to spend money on a new camera. I am looking for the title of a novel that I only caught part of on audio. It takes place within our current time frame and deals with the Moon getting struck and fragmented into (initially) 7 pieces by a high-speed asteroid that they called "The Agent".  Within a few weeks of this episode, scientists figure out the the Moon will continue to break down in a cascade reaction over the next couple of years until the planet gets bombarded by so much debris that it sterilizes Earth. The governments of the world frantically start to build a series of ships using swarming concepts to evacuate the planet as much as possible... and that's all I have heard so far.  Thanks for any info. We have 10 PC with some version of Ubuntu and only remote access. While doing some upgrades to custom software I did not notice that the line endings in some scripts were Windows version (CR+LF) and not the Unix version (LF). So now when I want to launch the script it gives an error:   bash: /usr/local/bin/portsee: /usr/bin/python^M: bad interpreter: No such file or directory   Is there a way to change all line endings in a script from terminal. The thing is that I can not install any new software to this group of PC-s. What is the relationship between ISO, aperture, and shutter speed? I thought I remembered hearing the food agency  say that you should never reheat chicken meat after the initial cooking. However, I cannot find the statement of it anymore. Now I'm starting to suspect my memory.  Could this statement be true?  Is it unsafe to reheat chicken? Why did Harry's father emerge before his mother in HP and the Goblet of Fire? In Harry Potter book 4 (Goblet of Fire) Harry's wand 'links' with Voldemort's during their duel, and Voldemort's wand begins 'spitting out' each spell it had cast, in reverse order.  This produces false 'ghosts' of people he had killed with .  In the US printing, James Potter appears, followed by Lily.  If the spell order was supposed to be reversed, why did Harry's father's "ghost" emerge before his mother's, since it's repeatedly stated (before and after) that he died first? How to disable the touchpad? I want my touchpad to be disabled when I use my mouse. How can I do that? touchpad-indicator has stopped working on 11.10. It used to work on 11.04. Gnome3 is not a solution as I don't like it and find it buggy. I have a set of Photoshop files which consist of a base image with a series of layers with colored overlays. The overlays are labeled using the layer names.  My task is to get these overlays as SVG paths, somehow preserving the labels. (If I can preserve the fill colors as well, that would be cool, but we can define arbitrary fill colors if needed.)  So far we have tried exporting the layers as Illustrator paths, and then exporting to SVG from Illustrator. This gets us reasonable SVG paths, but (a) we lose the labels, and (b) if a layer has more than one discrete section in its overlay, it is separated into several paths.  Is there a way to get these layers into SVG while retaining the labels? Or should we do our Export > Illustrator > SVG  route on a layer-by-layer basis?  We're working with CS5, if that's important.  ETA to answerers: We've long since finished this project and delivered the job, so I can't accept an answer, but feel free to pitch in your potential solutions for others. DNS subdomain (child) NS records If we have example.com we would setup things something like this: $ORIGIN example.com. @  1D  IN  SOA ns1.example.com. hostmaster.example.com. (                   2002022401 ; serial                   3H ; refresh                   15 ; retry                   1w ; expire                   3h ; nxdomain ttl                  )           IN  NS     ns1.example.com.           IN  NS     ns2.example.com.  since in the parent zone .com. there is already NS record for the example.com. child zone and A glue record for the ns1.example.com. for what purpose do we state NS records again in the child zone? and also, do we need to state A record for the name servers in the child zone itself? Scaling problem with fillbetween in pgfplots I've tried to install Ubuntu on a VMWare Virtual Machine, but it never gets past the  bootloader :  ISOLINUX 4.01 debian-20100714 ETCD Copyright (C) 1994-2010 H. Peter Anvin et al No DEFAULT or UI configuration directive found! boot: _   I've also tried to burn this .iso image to a CD and go from therem but I got the same problem.  Some more details :   VMWare Server 2.0.2 Build 203138 on Windows 2008 R2 ubuntu-10.10-desktop-i386.iso image used (downloaded yesterday evening) Marketing Cloud custom url expiration Prove that an infinite ring with finite quotient rings is an integral domain How can we show that if $R$ is an infinite commutative ring and $R/I$ is finite for every nonzero $I \unlhd R$, then $R$ is an integral domain?   I tried proceeding by contradiction: assume $a$,$b$ $\in R \backslash \{0\}$ and $ab=0$; then $R/(a)$ and $R/(b)$ must be finite, say $R/(a)=\{k_i + (a) : 1 \leq i \leq m\}$ and $R/(b)=\{l_j + (b) : 1 \leq j \leq n\}$. Does this mean $R$ must be finite? Or what about using the fact that $R/(a,b)$ finite?  Thanks for any help with this! What is wrong with using inline functions? While it would be very convenient to use inline functions at some situations,  Are there any drawbacks with inline functions?  Conclusion:  Apparently, There is nothing wrong with using inline functions.  But it is worth noting the following points!   Overuse of inlining can actually make programs slower. Depending on a function's size, inlining it can cause the code size to increase or decrease. Inlining a very small accessor function will usually decrease code size while inlining a very large function can dramatically increase code size. On modern processors smaller code usually runs faster due to better use of the instruction cache.  The speed benefits of inline functions tend to diminish as the function grows in size. At some point the overhead of the function call becomes small compared to the execution of the function body, and the benefit is lost  There are few situations where an inline function may not work:   For a function returning values; if a return statement exists. For a function not returning any values; if a loop, switch or goto statement exists.  If a function is recursive.   The __inline keyword causes a function to be inlined only if you specify the optimize option. If optimize is specified, whether or not __inline is honored depends on the setting of the inline optimizer option. By default, the inline option is in effect whenever the optimizer is run. If you specify optimize , you must also specify the noinline option if you want the __inline keyword to be ignored. TeXLive Pretest 2018: beamer and subfig collide \documentclass{beamer}  \usepackage{subfig}  \begin{document}  test  \end{document}   returns undefined control sequence \@@magyar@captionfix  (It was not so in January; I am on fully updated pretest) $f:I=[\pi,2\pi]\to \mathbb{R}^2$ be given by $f(t)=(\cos t,\sin t)$  which of the following are necessarily correct?  $1$. $\exists t_0\in I$ such that $f'(t_0)=\frac{1}{\pi}(f(2\pi)-f(\pi))$  $2$. $\nexists t_0\in I$ such that $f'(t_0)=\frac{1}{\pi}(f(2\pi)-f(\pi))$  $3$.$\exists t_0\in I$ such that $\pi||f'(t_0)||\ge ||(f(2\pi)-f(\pi)||$  $4$. $f'(t)=(-\sin t,\cos t)\forall t$  $4$ is clearly true, $1$ is true by Mean Value Theorem as $f$  satisfies all the conditions of MVT? have no idea of $2$ and $3$, Thank you for help How to reset the terminal properties and preferences? How do I reset the Windows XP Administrator password?