Folks can you explain me in which condition I should go with Interface and at which condition should I prefer Abstract class ... ? keep in mind I am not asking difference between Interface and Abstract class.
This may be a generic OOP question. I wanted to do a generic comparison between an interface and an abstract class on the basis of their usage.   When would one want to use an interface and when would one want to use an abstract class?
loading a view in popup hi i'm trying to display a view in a popup but unable to get a solution. i tried   colorbox node module popup views integration module   Is there any better way to display a view as a popup ? Let's say we have one black hole that formed through the collapse of hydrogen gas and another that formed through the collapse of anti-hydrogen gas. What happens when they collide? Do they (1) coalesce into a single black hole or do they (2) "annihilate" into radiation?  One would expect (1) to be the case if the No Hair Theorem were to hold. So I guess what I'm really asking for is a modern understanding of this theorem and its applicability given what we know today. GCSE: Find the number of person that will go to a party Take the following class as an example:  class Sometype {     int someValue;      public Sometype(int someValue)     {         this.someValue = someValue;     } }   I then want to create an instance of this type using reflection:  Type t = typeof(Sometype); object o = Activator.CreateInstance(t);   Normally this will work, however because SomeType has not defined a parameterless constructor, the call to Activator.CreateInstance will throw an exception of type MissingMethodException with the message "No parameterless constructor defined for this object." Is there an alternative way to still create an instance of this type? It'd be kinda sucky to add parameterless constructors to all my classes. What does a de Broglie wave look like? What does a  wave look like? Are de Broglie waves transverse or longitudinal?   Can they be polarized?    What about the de Broglie wave of a ground state neutral spin-zero Helium 4 atom?   What experimental evidence do we have that supports the detailed nature of a de Broglie wave?     I have always assumed that de Broglie waves were mathematically  identical to electromagnetic waves, but I just realized there is no basis for this assumption, and in fact it must be false, unless there is an analogue to both the magnetic and the electric components of the electromagnetic wave.  So what does a de Broglie wave "look like"? How does the Ranger's Extra Attack feature work with Two-Weapon Fighting? I think I know the answer to this one but I'm double checking.  At the 5th level the Ranger gets Extra Attack, which lets them attack a second time during the Attack action. If they are fighting with 2 weapons, the second weapon normally uses their bonus action.  Does this mean when using the Extra Attack and using two weapons, a ranger can attack twice during the Attack action, and still make 1 extra attack as a bonus action, for a total of 3 attacks? Show that if $n$ is not divisible by $2$ or by $3$, then $n^2-1$ is divisible by $24$.   I thought I would do the following ... As $n$ is not divisible by $2$ and $3$ then $$n=2k+1\;\text{or}\\n=3k+1\;\text{or}\\n=3k+2\;\;\;\;$$for some $n\in\mathbb{N}$. And then make induction over $k$ in each case.$$24\mid (2k+1)^2-1\;\text{or}\\24\mid (3k+1)^2-1\;\text{or}\\24\mid (3k+2)^2-1\;\;\;\;$$This question is in a text of Euclidean Division I'm reviewing, and I wonder if there is a simpler, faster, or direct this way. How do I detect orientation on app launch for splash screen animation on iPad! Find $\,\lim_{x\to 1}\frac{\sqrt[n]{x}-1}{\sqrt[m]{x}-1}$ Do proposals on Area 51 expire? Is there any kind of time frame in which new proposals are expected to attain the requisite number of followers to move to the next phase?  I can see where if it takes a year to gather enough followers to take the proposal to beta then maybe the proposal can come into question, but I can also see where others might take longer.  Or is the thought to go ahead and let it take as long as it takes and then it'll all get sorted out during the beta period? Can I travel to Paris for a day with a single entry visa for Schengen from Switzerland? I am visiting a friend in Switzerland for ten days. I have already got visitor's visa for the same on my Indian passport. Particulars mentioned on my visa are:  1. 'Etats Schengen' , 2. Single entry 3. Dates of visit. &amp; 4. Type of visa : C.  I understand that having already got ‘Etats Schengen' visa, I can travel to all Schengen countries.  I am also planning to visit Paris for a day during my stay in Switzerland. However, I never mentioned this in my visa application. I am planning to take a train from Geneva to Paris and book a hotel in Paris for one night. Can I possibly plan my Paris trip this way as I have Schengen visa, or I am not allowed to travel out of Switzerland as I never mentioned this in my visa application?   Also what does Single entry on my Schengen visa means: does it mean that I can enter and leave Switzerland only once or it means that I can enter and leave the Schengen region only once. Add Word Limit to Posts Prove every element of $G$ has finite order. prove inequality through mean value theorem How to find out if an item is present in a std::vector? All I want to do is to check whether an element exists in the vector or not, so I can deal with each case.  if ( item_present )    do_this(); else    do_that(); Studying the equation $\ln(x)- 1+ x^2=0$ "He was telling me that he is going..." vs. "He told me that he is going..." Prove the divergence of the sequence $\left\{ \sin(n) \right\}_{n=1}^{\infty}$. I am looking for nice ways of proving the divergence of the sequence $\left\{x_n\right\}_{n=1}^{\infty}$ defined by $$x_n=\sin{(n)}.$$ One (not so nice) way is to construct two subsequences: one where the indexes are picked such that they lie in the intervals  $$I_k=\left(\dfrac{\pi}{6}+2\pi(k-1),\dfrac{5\pi}{6}+2\pi(k-1)\right)$$ and one where they lie in $$J_k=\left(\dfrac{7\pi}{6}+2\pi(k-1),\dfrac{11\pi}{6}+2\pi(k-1)\right).$$ If ${x_n}$ converges, then all its subsequences must converge to the same limit, but here the first subsequence has all its values in the interval $\left[ \frac{1}{2}, 1\right]$ while the second has its values in $\left[-1,-\frac{1}{2}\right]$. Contradiction.  Filling the details of this proof is rather tedious and not very elegant. Anyone has a better idea? Calculate probability (area) under the overlapping area of two normal distributions Possible Duplicate:             What is correct? The jury was divided or The jury were divided? I am told that the latter is accurate because all of the jury do not have the same opinion in the particular case. Then, how does the subject verb agreement fit in 'The jury is still out' ? I mean, 'The jury is out' would allude to a situation were the opinion on a matter is (are?) still divided.