computer-science

I have found several algorithms that explain how to find strongly connected components in a directed graph, but none explain why you would want to do this. What are some applications of strongly connected components? You should check out Tim Roughgarden's Introduction to Algorithms course on Coursera. For every algorithm he goes over, he explains some applications of it. Very useful, and makes one see the value of studying algorithms! The use of strongly connected components that I remember him saying is that one could use it to find groups of people who are more closely related in a huge set

What are futures? It's something to do with lazy evaluation. Motti There is a Wikipedia article about futures. In short, it's a way to use a value that is not yet known. The value can then be calculated on demand (lazy evaluation) and, optionally, concurrently with the main calculation. C++ example follows. Say you want to calculate the sum of two numbers. You can either have the typical eager implementation: int add(int i, int j) { return i + j; } // first calculate both Nth_prime results then pass them to add int sum = add(Nth_prime(4), Nth_prime(2)); or you can use the futures way using C+

In the book coders at work , the author asks "How do you use invariants in your code". Please explain what this question means. I saw class invariants on wiki , but the example is in Java and I am not skilled enough in Java to relate this example to C#. .NET 4.0 introduces invariance, covariance, and contravariance and is well explained here. Invariance is so broad. The authors usage of the word seems unit test related. For those that read the book, what does the author mean? Are we talking about making an assumption and simply testing the validity after the unit test? The word invariant doesn