Browse questions answered by Jon Skeet

readLine for reading multiple lines without a loop?

So my servlet is reading a url link from another servlet and then publishing the article associated with it. All the articles are in a single .txt file with each article on its...

I would strongly advise you to separate out the "reading the data" from the "outputting HTML" sections of your code. It looks like you should create a data structure for an article, with properties for whatever the different bits in each... more 9/1/2014 9:12:00 PM

Getting Week number of year starting from April

I'm currently using this snippet: private string GetCurrentWeek() { // Return a string to be used in the TextBox control on the Main Form DateTimeFormatInfo dfi =...

I'm assuming you want week 1 to begin on April 6th always, and be 7 days long, rather than having some rule like "Weeks always start on Mondays". Basically this is just a matter of: Working out which tax year you're in Finding the start... more 8/31/2014 7:39:00 PM

Is a private final String[] array threadsafe as long as its protected?

Let's say I have a static final String[] array that is only read but will not be modified private static final String[] myArray = { "Col1", "Col2", "Col3" }; If I can guarantee...

Yes, it's fine so long as nothing ever writes to the array. It will be initialized during type initialization, so all threads will "see" the values. For the sake of readability you might want to consider using an immutable collection... more 8/31/2014 4:42:54 PM

Why does this method keep returning dynamic despite the return type in the signature?

So the type being returned by the activator (not shown here) is just a POCO that I created. Nothing special about it at all. But despite, the return type of GetWrapper or...

I strongly suspect that either child1 or child1.kind are of type dynamic, meaning that the expression is deemed to be a dynamically-bound expression, despite everything else. Here's a short but complete example to demonstrate what I... more 8/30/2014 8:46:44 PM

Can I use a member of an object that requires a cast without using a temporary variable?

I'd like to know if there is some way to use the method of a casted object without creating a new variable. In other word, is there a way to do this: abstract class event {...

This is a problem with operator precedence. . has a higher precedence than a cast, so this: (loop) (e).a is being treated as: (loop) ((e).a) You want to cast and then use the result in the member access - so you need to bind the cast... more 8/30/2014 5:12:59 PM

Can obj.GetType().IsInterface be true?

While doing something almost completely irrelevant, a question popped into my head: Can an expression of the form obj.GetType().IsInterface ever be true in a codebase consisting...

Can an expression of the form obj.GetType().IsInterface ever be true in a codebase consisting exclusively of C# code? Yes - but probably not the way you were thinking of: using System; public class EvilClass { public new Type... more 8/30/2014 4:40:49 PM

Is this use of varargs safe?

I have a sort of util method to transform a varargs of a type into an array of that type - it looks like this: public K[] array(K... ks) { return ks; } The use case is so...

No, it's not safe - if called from another method which is using generics. Here's a complete example which looks okay, but throws an exception: class Utility<K> { public K[] array(K... ks) { return ks; } ... more 8/30/2014 4:28:56 PM

Does LINQ try to solve things in one pass?

Say we have list.Where(p=>p.Number > n).Select(p=> p.Name).Where(n=> n.StartsWith(a)).ToList(); will this be ran one pass algorithm or it will be 3 passes?

It will build up the list in one pass, due to the way that LINQ streams the data. For example, take this: var query = list.Where(p => p.Number > n); That in itself doesn't look at any of the elements of the list. Instead, it... more 8/29/2014 5:32:24 PM

How to get type of inherited generic

I have these classes: public abstract class BaseClass{} public class CustomerService : BaseClass<Customer>{} public class ProductService : BaseClass<Product>{} public...

If you're just looking for a class whose direct base type is the relevant BaseClass<T>, you can use code like this: var targetBaseType = typeof(BaseClass<>).MakeGenericType(entityType); var type =... more 8/29/2014 4:55:44 PM

push(int[][]) in a stack is duplicating the same value Java

I have a 2 dimensional array and stack: int[][] data = new int[][]; Stack<int[][]> undoList = new Stack<int[][]>(10); I wanna add the data after every change to...

You're making changes to the array - but you're not putting the array itself on the stack... you're putting a reference to the array on the stack. You're basically pushing the same reference several times. If you want independent values,... more 8/29/2014 4:51:38 PM