comparator

I tried reproducing the code below on eclipse. I get an error telling me that I have to implement all the inherited methods (because Comparator is an interface). The type new Comparator(){} must implement the inherited abstract method Comparator.reversed() . There are many of these methods and the only one I want to overwrite is compare. Do I have to implement all the other methods or is there a way to specify I don't need to implement them? I understand that I will have to do it because of the contractual nature of an interface, but what if I just need to change one method? static Map

I'm trying to make a comparator that can take any type of an element to compare. I'm unsure about how to create the class. I just want it to compare two elements of the same type (But whatever type the client gives it, ex: Integer, String, Double, etc...) to see which one is greater then the other. public class InsertionComparator implements Comparator<T> { /** * Compares two elements. * * @param f1 The first element you want to compare. * @param f2 The second element you want to compare. * @return -1,0,1 Whether or not one is greater than, less than, * or equal to one another. */ public int

If I implement a custom comparator is it considered good practice to overide equals besides compare ? Additionally is there a defined contract for a Comparator ? assylias The contract of Comparator is defined in its javadoc . In particular: Caution should be exercised when using a comparator capable of imposing an ordering inconsistent with equals to order a sorted set (or sorted map). Suppose a sorted set (or sorted map) with an explicit comparator c is used with elements (or keys) drawn from a set S. If the ordering imposed by c on S is inconsistent with equals, the sorted set (or sorted map

I just started to learn C++, Half of the time I don't know what am I doing, spend hours and hours searching on Google and blindly put codes inside my project, this might be a basic question, but I just can't seems to get it right. This is the requirement of my assignment, I need to have these: in the Edge class: public: bool operator()(Edge*, Edge*) in the Graph class: private: priority_queue<Edge*, vector<Edge*>, Edge> edges I have problem declaring the priority_queue. Details: If I directly use these, the edge class will give me an error of "must have an argument of class", I understand that

I would like to sort alphanumeric strings the way a human being would sort them. I.e., "A2" comes before "A10", and "a" certainly comes before "Z"! Is there any way to do with without writing a mini-parser? Ideally it would also put "A1B1" before "A1B10". I see the question "Natural (human alpha-numeric) sort in Microsoft SQL 2005" with a possible answer, but it uses various library functions, as does "Sorting Strings for Humans with IComparer" . Below is a test case that currently fails: #include <set> #include <iterator> #include <iostream> #include <vector> #include <cassert> template

In Guava, given a Collection<E> and an element e of type E that I know is in the collection, I'd like to create a custom Ordering<E> that sorts e first and then the rest of the collection. However, the way to get there seems awfully complicated: Collection<String> values = ImmutableList.of("apples", "oranges", "pears"); String first = "oranges"; List<String> remainingValues = newArrayList(values); // this remainingValues.remove(first); // seems Ordering<String> myOrdering = // very Ordering.explicit(first, remainingValues.toArray( // complicated! new String[remainingValues.size()])); // is