C scanf not working in recursive function
scanf() misbehaving
In a perfect world, the so-important advice "do not reinvent the wheel" would be extensively followed. In practice, everyday millions of wheels are reinvented simply because someone didn't know an existing solution for a specific problem. The best way to find a library, today, is googling it, but it's not always obvious which keywords to use. The lack of a tool for finding solutions is very counterproductive for the dev world as a whole. Stack Overflow is not very receptive for recommendation threads. So what about a new SE for it? I was hoping someone could give an overview as to how the Lie groups $SO(3)$ and $SU(2)$ and their representations can be applied to describe particle physics?  The application of Lie groups and their representations is an enormous field, with vast implications for physics with respect to such things as unification, but I what specifically made these groups of physical importance and why there study is useful.  I have just started studying these two groups in particular, but from a mathematical perspective, I'd very much appreciate understanding some sort of physical motivation. Possible Duplicate:          There are a lot of really screwed up configurations out there, because people didn't take a minute to sit down and think about something as simple as the name for their Active Directory forest. I'm asking this question to self-answer so that this knowledge can be more readily available. If you think you have a better answer, by all means add your input (but be prepared to defend it!)   So, what should I name my new Active Directory? Function pointers/delegates in Java? For my Java game server I send the Action ID of the packet which basically tells the server what the packet is for. I want to map each Action ID (an integer) to a function. Is there a way of doing this without using a switch? The exercise is: Prove that $-(-v)=v$ for every $v \in V$  Proof Suppose  $v \in V$ and $V$ is a vector space. Then $-(-v) \in V$ as result of the scalar multiplication property and $-(-v)=-(-1\cdot v)=-1 \cdot(-1\cdot v) =(-1 \cdot-1)\cdot v = 1 \cdot v = v $ The desired result $-(-v)=v$ holds.  The solution manual gives the proof:  Proof   I just wanted to make sure that the way I did the proof isn't missing anything?Thanks Geomagnetic reversal? I have always been told that the geomagnetic field acts "as if" there were a bar magnet inside the Earth. I now this is not true, but I feel that knowing what is actually going on would help me understand the answer to the question that I'm about to ask:  Why does geomagnetic reversal happen? Is it something gradual or relatively fast?  (What is the origin of the geomagnetic field? Can we answer my questions starting from this mechanism? Tasks in custom Environment I need to wrap a tasks environment inside a custom \NewEnviron. Apparently, tasks chokes on code besides its \task or \item due to the , presumably causing it to do so on \BODY. Any way to get around this? Exact error given is "Something's wrong--perhaps a missing \item", as per:  \documentclass[a4paper]{book} \usepackage{environ} \usepackage[more]{tasks}  \NewTasks[style=enumerate,counter-format=tsk[1]),label-width=2ex]{mytaskenum}[\item](3) \NewEnviron{mytaskenv}[1][Exercises]{   % Misc. stuff to precede the tasks env here   \begin{mytaskenum}   \BODY   \end{mytaskenum}   % Misc. stuff to follow }{}  \begin{document}  \begin{mytaskenv}   \item item 1   \item item 2   \item item 3 \end{mytaskenv}  \end{document} Suppose $n$ is an even positive integer and $H$ is a subgroup of $\mathbb Z/n \mathbb Z$. Prove that either every element of $H$ is... Suppose $n$ is an even positive integer and $H$ is a subgroup of $\mathbb Z/n\mathbb Z$. Prove that either every element of $H$ is even or exactly half of its elements are even. (Gallian, Contemporary Abstract Algebra, Exercise 24, Chapter 3.) Is gravitational time dilation different from other forms of time dilation? Is gravitational time dilation caused by gravity, or is it an effect of the inertial force caused by gravity?    Is gravitational time dilation fundamentally different from time dilation due to acceleration, are they the same but examples of different configurations?    Could you recreate the same kind of time dilation without gravity using centrifugal force? Is adding a time dummy the same as estimating by within-time fixed effects? For one of the clients, I have spin up a modern communication site collection and on the landing page of the same, I am seeing 'Get the mobile app' showing up, I was able to hide the 'feedback' button using css but no luck with Get the mobile app button.  Can someone please share css to hide 'get mobile app' button, appreciate the help. The shop is five minutes away.     According to the dictionary, away is an adverb. An adverb modifies a verb. In the above example, what word does away modify? Why is away not an adjective?       The shop is five meters tall.     tall is an adjective in the second example. It modifies five meters (does it?). So why is away an adverb? Why does the amount of energy transferred depend on distance rather than time? The change in energy of an object can be determined by the work equation, where work is the change in energy:  $$ W = F \cdot d $$  I conceptualize the transfer of energy as simply a series of small "packets" of energy being transferred at every Planck length. These small "packets" of energy add up to the total energy transferred (i.e. work). I'm not sure if this conceptualization is correct, so correct me if I am wrong.  However, it makes me wonder why the amount of energy transferred is dependent on distance and not time.  $$ m_1 = 10~kg \\ m_2 = 20~kg \\ W_1 = (10~N)\cdot(5~m) = 50~J \\ W_2 = (10~N)\cdot(5~m) = 50~J \\ W_1 = W_2 \\ t_1 \neq t_2 $$  If I apply a constant force on an object, why isn't the energy transferred at a constant rate with respect to time? The energy transfer rate varies dependent on how long it takes to cover the set distance.  In other words: why is the energy transferred consistent per unit of distance, and not per unit of time? 1.7.4 Problem with mobs spawning I have just updated to Minecraft 1.7.4 and now all of a sudden there are barely any mobs spawning.  I checked to make sure that I was in normal difficult and I saw 1 creeper but that is all.  Also I tried different difficulties. Another thing - mobs seem to to spawn normally in the nether and all other mobs except aggressive mobs spawn like they should.  Please if you know how to fix this, please help! I can't find a definitive answer for this. As far as I know, you can't have multiple __init__ functions in a Python class. So how do I solve this problem? Suppose I have a class called Cheese with the number_of_holes property. How can I have two ways of creating cheese objects...  One that takes a number of holes like this: parmesan = Cheese(num_holes = 15) And one that takes no arguments and just randomizes the number_of_holes property: gouda = Cheese()  I can think of only one way to do this, but this seems clunky: class Cheese():     def __init__(self, num_holes = 0):         if (num_holes == 0):             # Randomize number_of_holes         else:             number_of_holes = num_holes  What do you say? Is there another way? What is the name of the package for R? I tried aptitude search r, but (unsurprisingly), there are waaaay too many results to sift through. Where to start with Oracle? This question only needs one answer: a list of great resources for getting started with Oracle, including Database Administration, PL/SQL and SQL.   You may find your question has been closed as a duplicate of this one, if so, please don't be offended: we are trying to be as helpful as we can without . Closing a question as a duplicate of this one is us saying "What you really need is to spend some time reading some of the best resources available rather than have your specific question answered right now. If you do get through these resources, you'll soon be back with more ! Force JavaScript exception/error when reading an undefined object property? Authenticate to Stack Exchange using GitHub I've seen sign in methods using  as an authentication provider, for example : (AWS Cloud9)        Is it possible to authenticate into Stack Exchange using this method? At the moment there's other methods such as OpenID, Google, Yahoo and Facebook, but it would be interesting to also have the GitHub authentication. Given Newton's third law, why are things capable of moving?