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Patrick posted his solution earlier this week. I figure it was time to add mine. Also, Octavio Hernandez pointed out in the comments to problem 8 that he had discussed similar code constructs in his blog a while back. Problem 10 asks for the sum of all primes less than 2 million. It's also one line...

My last Lightning Talk should how you can mix constructor calls and object initializers. It's a useful technique that can keep you from writing too much code you don't need. To see what I mean, start with this simple person class: 1: class Person 2: { 3: public string FirstName 4: { 5: get; 6...

I was going to wait a bit to post this, but Patrick Steele posted his solution , so I figured I should post mine. Patrick took the straight out brute force approach. I decided to think a bit differently and use the some LINQ code to generate my answer. The problem is to find the only Pythagorean triplet...

Yes, it's true that I've been very lax in working on these problems. It's been a combination of the day job, finishing all the editing tasks on "More Effective C#", and actually trying to keep the personal life intact. The 7th problem is quite straightforward: find the 10,001st...

I had a question from a colleague the other day about extension methods. I'm simplifying a little, but he was looking for a way to ensure that every source file used the same set of extension methods. There is one way to enforce this, but it does have an effect on your code organization. Section...

One of my last Visual Studio Magazine article discussed object validation and object invariants. I received a great email discussing questions about how to handle UI validation in this world. My recommendation in the article was that classes should be responsible for their own state. Furthermore, they...

I received this question in email from one of my readers, and I thought it would be of general interest: I find myself with two arrays of the same size and I want to create a third that combines each element. What I want is something similar to var S3 = S1.foreach(S2, (s1, s2) => s1 + s2); this would...

Well, I'm back from the MVP Summit, and it seems that tradition mandates a summary of the trip. But there is one problem: The best content was all under NDA. Most MVPs spend their time with members of the product team for their award, and other teams that are related. For me, that obviously means...

Euler Problem six asks you to find the difference between the sum of squares and the square of the sum for the natural numbers 1 through 100. I took the easy route, and made a brute force implementation in C#. There are a couple new bits of LINQ syntax here. This query creates two different anonymous...

Well, it's time to post another solution and look at how LINQ and C# 3.0 can create elegant code for these problems. The fifth problem asks you to find the smallest number that is divisible by all the natural numbers from 1 through 20. You can trivially find the answer like this: 1 private static...