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  • Network communication for a turn based board game

    - by randooom
    Hi all, my first question here, so please don't be to harsh if something went wrong :) I'm currently a CS student (from Germany, if this info is of any use ;) ) and we got a, free selectable, programming assignment, which we have to write in a C++/CLI Windows Forms Application. My team, two others and me, decided to go for a network-compatible port of the board game Risk. We divided the work in 3 Parts, namely UI, game logic and network. Now we're on the part where we have to get everything working together and the big question mark is, how to get the clients synchronized with each other? Our approach so far is, that each client has all information necessary to calculate and/or execute all possible actions. Actually the clients have all information available at all, aside from the game-initializing phase (add players, select map, etc.), which needs one "super-client" with some extra stuff to control things. This is the standard scenario of our approach: player performs action, the action is valid and got executed on the players client action is sent over the network action is executed on the other clients The design (i.e. no or code so far) we came up with so far, is something like the following pseudo sequence diagram. Gui, Controller and Network implement all possible actions (i.e. all actions which change data) as methods from an interface. So each part can implement the method in a way to get their job done. Example with Action(): On the player side's Client: Player-->Gui.Action() Gui-->Controller.Action() Controller-->Logic.Action (Logic.Action() == NoError)? Controller-->Network.Action() Network-->Parser.ParseAction() Network.Send(msg) On all other clients: Network.Recv(msg) Network-->Parser.Deparse(msg) Parser-->Logic.Action() Logic-->Gui.Action() The questions: Is this a viable approach to our task? Any better/easier way to this? Recommendations, critique? Our knowledge (so you can better target your answer): We are on the beginner side, in regards to programming on a somewhat larger projects with a small team. All of us have some general programming experience and basic understanding of the .Net Libraries and Windows Forms. If you need any further information, please feel free to ask.

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  • How Can I up my Street Cred in the coding world

    - by RedEye
    I know this isn't directly related to a specific coding problem. It's a more general programming question. I'm a n00b... Been coding for 1 year, and it's where I belong. I want to get hardcore and put everything I have into it. I started with C++ and now I'm into C#. I love it all. What can I do to up my game and up my respect in the programming world?

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  • What are the things I use every day programmed with?

    - by sub
    It isn't so interesting to find out what this text editor here or that IRC client there was programmed with, also it isn't really hard and neither are there really suprising things to come out. Wow so it was programmed in Python, I didn't expect that. What I'm asking is: What are the things that we daily see, use or generally need programmed with? To name a few (really only a few of those out there): My alarm clock It has many features so it would probably be hard programming it with assembler or whatever, so did they probably use a programming language? If yes, which? My electrical tooth brush The (stupid) board computer of my car. (6 years old, has few features but a red LED display showing me how cold/warm it is outside and how much gas I'm using up per hour at the moment) Those (old) plastic mini-mini computers with the LCD(?) displays that only had one game available on them: PacMan, tetris or so. I'm not directly thinking of this but it may be similar: Other, probably more interesting, things I didn't mention

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  • Good working habits to observe in project development?

    - by Will Marcouiller
    As my development experience grows, I see fit to stick to best practices from here and there to build somehow my own working practices while observing the conventions, etc. I'm currently working on a project which my goals is to graduate the security access model from an environment's Active Directory to another environment's automatically. I don't know for any of you, but as far as I'm concerned, I meet some real difficulties sticking to only one way, then develop. I mean, I learn something new everyday while visiting SO, and recently wanted to get acquainted with generics. On the other hand, I better know the Façade pattern which proved to be very practical in transactional programming in process systems. This seems to be less practical for desktop application as there are plenty of variables to consider in a desktop application that you don't have to care in transactional programming, as you're playing only with information data. As for my current project, I have: Groups; Organizational Units; Users. Which are all considered an entry in the Active Directory. This points out to be a good candidate for generics, as also approached this way by Bart de Smett's Linq to AD on CodePlex. He has a DirectorySource<T>, and to manage let's say groups, then he instantiate a source with the proper type: var groups = new DirectorySource<Group>(); This seems to be very a good way of doing. Despite, I seem to go from one pattern to another and I don't seem to be able to strictly stick to one. While I'm aware that one must not stay with only one way of doing, since each pattern statisfies certain advantages, while also illustrating disadvantages under some usage conditions, I seem to want to develop with both patterns having a singleton Façade class with the underlying factories which represent the sub systems: GroupsFactory; UsersFactory; OrganizationalUnitsFactory. Each of the factories offers the possible operations for their respective entity (group, user, OU). To make a very long story short, I often have plenty of ideas while developping and this causes me some trouble, as I go from an idea to another feeling completely lost after a while. Yet I understand the advantages and disavantages, I have no trouble choosing from one pattern to another depending on the situation. Nevertheless, when it comes to programming itself, if I'm not part of a team, I feel sometimes like I can't do anything good. That is, because I can't stand not doing something "perfect" the first time. The role I play within the project is both: the project manager and the programmer. I am more comfortable in the project manager role, architectural role, analytical role than the developer's. Has any of you some good habbits to observe in project development? Thanks to you all! =)

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  • Are there any purely functional Schemes or Lisps?

    - by nickname
    Over the past few months, I've put a lot of effort into learning (or attempting to learn) several functional programming languages. I really like math, so they have been very natural for me to use. Simply to be more specific, I have tried Common Lisp, Scheme, Haskell, OCaml, and (a little bit of) Erlang. I did not like the syntax of OCaml and do not have enough Erlang knowledge to make a judgment on it yet. Because of its consistent and beautiful (non-)syntax, I really like Scheme. However, I really do appreciate the stateless nature of purely functional programming languages such as Haskell. Haskell looks very interesting, but the amount of inconsistent and non-extendable syntax really bothered me. In the interest of preventing a Lisp vs Haskell flame war, just pretend that I can't use Haskell for some other reason. Therefore, my question is: Are there any purely functional Schemes (or Lisps in general)?

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  • What is more interesting or powerful: Curry/Mercury/Lambda-Prolog/your suggestion.

    - by Bubba88
    Hi! I would like to ask you about what formal system could be more interesting to implement from scratch/reverse engineer. I've looked through some existing and rather open (open in the sense of free/open-source) projects of logical/declarative programming systems. I've decided to make up something similar in my free time, or at least to catch the general idea of implementation. It would be great if some of these systems would provide most of the expressive power and conciseness of modern academic investigations in logic and it's relation with computational models. What would you recommend to study at least at the conceptual level? For example, Lambda-Prolog is interesting particularly because it allows for higher order relations, but AFAIK (I might really be mistaken :)) is based on intuitionist logic and therefore lack the excluded-middle principle; that's generally a disatvantage for me.. I would also welcome any suggestions about modern logical programming systems which are less popular but more expressive/powerful. I guess, this question will need refactoring, but thank you in advance! :)

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  • Where does C# and the .NET Framework fail?

    - by Nate Bross
    In my non-programming life, I always attempt to use the approprite tool for the job, and I feel that I do the same in my programming life, but I find that I am choosing C# and .NET for almost everything. I'm finding it hard to come up with (realistic business) needs that cannot be met by .NET and C#. Obviously embedded systems might require something less bloated than the .NET Micro Framework, but I'm really looking for line of business type situations where .NET is not the best tool. I'm primarly a C# and .NET guy since its what I'm the most comfertable in, but I know a fair amount of C++, php, VB, powershell, batch files, and Java, as well as being versed in the web technologes (javascript, html/css). But I'm open minded about it my skill set and I'm looking for cases where C# and .NET are not the right tool for the job. The bottom line here, is that I feel that I'm choosing C# and .NET simply because I am very comfertable with it, so I'm looking for cases where you have chosen something other than .NET, even though you are primarly a .NET developer.

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  • Where/When do C# and the .NET Framework fail to be the right tool?

    - by Nate Bross
    In my non-programming life, I always attempt to use the appropriate tool for the job, and I feel that I do the same in my programming life, but I find that I am choosing C# and .NET for almost everything. I'm finding it hard to come up with (realistic business) needs that cannot be met by .NET and C#. Obviously embedded systems might require something less bloated than the .NET Micro Framework, but I'm really looking for line of business type situations where .NET is not the best tool. I'm primarly a C# and .NET guy since its what I'm the most comfertable in, but I know a fair amount of C++, php, VB, PowerShell, batch files, and Java, as well as being versed in the web technologes (JavaScript, HTML, and CSS). But I'm open minded about it my skill set and I'm looking for cases where C# and .NET are not the right tool for the job. I choose .NET and C# because I'm comfortable with it, but I'm looking for cases where it isn't appropriate.

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  • Is there any valid reason radians are used as the inputs to trig function in many modern languages?

    - by johnmortal
    Is there any pressing reason trig functions should use radian inputs in modern programming languages? As far as I know radians are typically ugly to deal with except in three cases: (1) You want to compute an arc length and you know the angle of the arc and (2) You need to do symbolic calculus with trig functions (3) certain infinite series expansion look prettier if the input is in radians. None of these scenarios seem like a worthy justification for every programming language I am familiar with using radian inputs for Sin, Cos, Tangent, etc... The third one sounds good because it might mean one gets faster computations using radians (very slightly faster- the cost of one additional floating point multiplication ) , but I am dubious even of that because most commonly the developer had to take an extra step to put the angle in radians in the first place. The other two are ridiculous justifications for all the added obscurity.

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  • Where/When does C# and the .NET Framework fail to be the right tool?

    - by Nate Bross
    In my non-programming life, I always attempt to use the approprite tool for the job, and I feel that I do the same in my programming life, but I find that I am choosing C# and .NET for almost everything. I'm finding it hard to come up with (realistic business) needs that cannot be met by .NET and C#. Obviously embedded systems might require something less bloated than the .NET Micro Framework, but I'm really looking for line of business type situations where .NET is not the best tool. I'm primarly a C# and .NET guy since its what I'm the most comfertable in, but I know a fair amount of C++, php, VB, powershell, batch files, and Java, as well as being versed in the web technologes (javascript, html/css). But I'm open minded about it my skill set and I'm looking for cases where C# and .NET are not the right tool for the job. The bottom line here, is that I feel that I'm choosing C# and .NET simply because I am very comfertable with it, so I'm looking for cases where you have chosen something other than .NET, even though you are primarly a .NET developer.

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  • What are the flavor-of-the-month technologies that have now become obscure?

    - by Andreas Grech
    For this question, I am looking for programming languages, technologies and standards that where considered as a flavour-of-the-month in their prominent time but have since been forgotten in today's programming world. Also, with what have they been replaced? I am relatively new to the software development industry compared to most of the people here (with just only 5 years of experience), and from this question I am looking to learn about some of the now-obscure technologies that have been around during your time. Just for clarification, what I mean by flavour-of-the-month is technologies that had been extensively in their time but today have become obscure and forgotten; maybe replaced by other better ones

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  • iphone singleton object synchronization

    - by user127091
    I'm working on an iphone app but this is probably a general question. I have a singleton Model class and there would be scenarios where multiple NSOperations (threads) would exist and work with the singleton object. If they all call the same method in this object, do i need to have some locking mechanism? Or can this method be executed only one at a time? I do not have a computer science background but my guess is that all threads would have their CALL to the same address (this method). Also can you please suggest a good beginner programming book that discusses general programming concepts. I don't have the brains for Knuth kinda books.

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  • Count the number of ways in which a number 'A' can be broken into a sum of 'B' numbers such that all numbers are co-prime to 'C'

    - by rajneesh2k10
    I came across the solution of a problem which involve dynamic-programming approach, solved using a three dimensional matrix. Link to actual problem is: http://community.topcoder.com/stat?c=problem_statement&pm=12189&rd=15177 Solution to this problem is here under MuddyRoad2: http://apps.topcoder.com/wiki/display/tc/SRM+555 In the last paragraph of explanation, author describes a dynamic programming approach to count the number of ways in which a number 'A' can be broken into a sum of 'B' numbers (not necessarily different), such that every number is co-prime to 3 and the order in which these numbers appear does matter. I am not able to grasp that approach. Can anyone help me understand how DP is acting here. I can't understand what is a state here and how it is derived from the previous state.

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  • What is the most efficient functional version of the following imperative code?

    - by justin.r.s.
    I'm learning Scala and I want to know the best way of expressing this imperative pattern using Scala's functional programming capabilities. def f(l: List[Int]): Boolean = { for (e <- l) { if (test(e)) return true } } return false } The best I can come up with is along the lines of: l map { e => test(e) } contains true But this is less efficient since it calls test() on each element, whereas the imperative version stops on the first element that satisfies test(). Is there a more idiomatic functional programming technique I can use to the same effect? The imperative version seems awkward in Scala.

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  • What did they program this toy with?

    - by Trix
    A rather strange question: I'm often asking myself with what programming languages things were created. I recently found this toy mini computer I played with when I was 13 or so at home. (Note: It is not one of those toy "notebooks", it's really small and came as an extra with a magazine) "Features": Hadware: LCD with a small field of pixels where the games were going on, besides that some stats such as score, highscore etc. Sounds and horrible music when started A really small "keyboard" with a wire Software: At least 14 or so games, from Snake over Tetris and Breakdown to some abomination of a car racing game A calculator Game selecting menu An alarm clock Inside there is a really small circuit board, I don't want to open the thing up now, though. Can you imagine if the games and "Operating System" of this thing where actually programmed using a language? If yes, what language could it be? If not with a programming language, how else was it created?

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  • How Do Sockets Work in C?

    - by kaybenleroll
    I am a bit confused about socket programming in C. You create a socket, bind it to an interface and an IP address and get it to listen. I found a couple of web resources on that, and understood it fine. In particular, I found an article Network programming under Unix systems to be very informative. What confuses me is the timing of data arriving on the socket. How can you tell when packets arrive, and how big the packet is, do you have to do all the heavy lifting yourself? My basic assumption here is that packets can be of variable length, so once binary data starts appearing down the socket, how do you begin to construct packets from that?

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  • What is it like working as a computer programmer

    - by Luke101
    I have a day job as an IT system administrator, but I do a lot of c# asp.net programming on my spare time. I have always wondered what its like to be a real software developer. I have taken a look at big CMS systems like umbraco and Dotnetnuke and said to myself that these developers must have decades of programming experience. Just the design of these products are overwhelming let alone the actual code. I just would like your comments on what it is like being a programmer.

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  • Which language should I learn to create a sudoku game?

    - by Brandan
    I'd like to learn a new programming language, something besides all the scripting languages I've used for the past many years (Ruby, JavaScript, Perl, PHP, bash). I figured it might be interesting to make a sudoku game since there are plenty of documented algorithms and it only requires fairly simple data structures. It might start out as either a generator or a solver of puzzles, not necessarily both and not necessarily with a GUI. My goal is primarily to learn some new programming concepts beyond MVC and UI design, secondarily for this thing to be pretty fast. Is there a language that particularly shines for these sorts of constraint satisfaction problems? Is it suited to a functional language like Haskell or a highly concurrent language like Erlang (say for solving puzzles much larger than 9 x 9)? Or is this question mostly meaningless?

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  • How to optimize dynamic programming?

    - by Chan
    Problem A number is called lucky if the sum of its digits, as well as the sum of the squares of its digits is a prime number. How many numbers between A and B are lucky? Input: The first line contains the number of test cases T. Each of the next T lines contains two integers, A and B. Output: Output T lines, one for each case containing the required answer for the corresponding case. Constraints: 1 <= T <= 10000 1 <= A <= B <= 10^18 Sample Input: 2 1 20 120 130 Sample Output: 4 1 Explanation: For the first case, the lucky numbers are 11, 12, 14, 16. For the second case, the only lucky number is 120. The problem is quite simple if we use brute force, however the running time is so critical that my program failed most test cases. My current idea is to use dynamic programming by storing the previous sum in a temporary array, so for example: sum_digits(10) = 1 -> sum_digits(11) = sum_digits(10) + 1 The same idea is applied for sum square but with counter equals to odd numbers. Unfortunately, it still failed 9 of 10 test cases which makes me think there must be a better way to solve it. Any idea would be greatly appreciated. #include <iostream> #include <vector> #include <string> #include <algorithm> #include <unordered_map> #include <unordered_set> #include <cmath> #include <cassert> #include <bitset> using namespace std; bool prime_table[1540] = { 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 }; unsigned num_digits(long long i) { return i > 0 ? (long) log10 ((double) i) + 1 : 1; } void get_sum_and_sum_square_digits(long long n, int& sum, int& sum_square) { sum = 0; sum_square = 0; int digit; while (n) { digit = n % 10; sum += digit; sum_square += digit * digit; n /= 10; } } void init_digits(long long n, long long previous_sum[], const int size = 18) { int current_no_digits = num_digits(n); int digit; for (int i = 0; i < current_no_digits; ++i) { digit = n % 10; previous_sum[i] = digit; n /= 10; } for (int i = current_no_digits; i <= size; ++i) { previous_sum[i] = 0; } } void display_previous(long long previous[]) { for (int i = 0; i < 18; ++i) { cout << previous[i] << ","; } } int count_lucky_number(long long A, long long B) { long long n = A; long long end = B; int sum = 0; int sum_square = 0; int lucky_counter = 0; get_sum_and_sum_square_digits(n, sum, sum_square); long long sum_counter = sum; long long sum_square_counter = sum_square; if (prime_table[sum_counter] && prime_table[sum_square_counter]) { lucky_counter++; } long long previous_sum[19] = {1}; init_digits(n, previous_sum); while (n < end) { n++; if (n % 100000000000000000 == 0) { previous_sum[17]++; sum_counter = previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[16] = 0; previous_sum[15] = 0; previous_sum[14] = 0; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000000000000 == 0) { previous_sum[16]++; sum_counter = previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[15] = 0; previous_sum[14] = 0; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000000000000 == 0) { previous_sum[15]++; sum_counter = previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[14] = 0; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000000000000 == 0) { previous_sum[14]++; sum_counter = previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000000000 == 0) { previous_sum[13]++; sum_counter = previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000000000 == 0) { previous_sum[12]++; sum_counter = previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000000000 == 0) { previous_sum[11]++; sum_counter = previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000000 == 0) { previous_sum[10]++; sum_counter = previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000000 == 0) { previous_sum[9]++; sum_counter = previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000000 == 0) { previous_sum[8]++; sum_counter = previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000 == 0) { previous_sum[7]++; sum_counter = previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000 == 0) { previous_sum[6]++; sum_counter = previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000 == 0) { previous_sum[5]++; sum_counter = previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000 == 0) { previous_sum[4]++; sum_counter = previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000 == 0) { previous_sum[3]++; sum_counter = previous_sum[3] + previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[3] * previous_sum[3] + previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100 == 0) { previous_sum[2]++; sum_counter = previous_sum[2] + previous_sum[3] + previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[2] * previous_sum[2] + previous_sum[3] * previous_sum[3] + previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10 == 0) { previous_sum[1]++; sum_counter = previous_sum[1] + previous_sum[2] + previous_sum[3] + previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[1] * previous_sum[1] + previous_sum[2] * previous_sum[2] + previous_sum[3] * previous_sum[3] + previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[0] = 0; } else { sum_counter++; sum_square_counter += ((n - 1) % 10) * 2 + 1; } // get_sum_and_sum_square_digits(n, sum, sum_square); // assert(sum == sum_counter && sum_square == sum_square_counter); if (prime_table[sum_counter] && prime_table[sum_square_counter]) { lucky_counter++; } } return lucky_counter; } void inout_lucky_numbers() { int n; cin >> n; long long a; long long b; while (n--) { cin >> a >> b; cout << count_lucky_number(a, b) << endl; } } int main() { inout_lucky_numbers(); return 0; }

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  • Which programming idiom to choose for this open source library?

    - by Walkman
    I have an interesting question about which programming idiom is easier to use for beginner developers writing concrete file parsing classes. I'm developing an open source library, which one of the main functionality is to parse plain text files and get structured information from them. All of the files contains the same kind of information, but can be in different formats like XML, plain text (each of them is structured differently), etc. There are a common set of information pieces which is the same in all (e.g. player names, table names, some id numbers) There are formats which are very similar to each other, so it's possible to define a common Base class for them to facilitate concrete format parser implementations. So I can clearly define base classes like SplittablePlainTextFormat, XMLFormat, SeparateSummaryFormat, etc. Each of them hints the kind of structure they aim to parse. All of the concrete classes should have the same information pieces, no matter what. To be useful at all, this library needs to define at least 30-40 of these parsers. A couple of them are more important than others (obviously the more popular formats). Now my question is, which is the best programming idiom to choose to facilitate the development of these concrete classes? Let me explain: I think imperative programming is easy to follow even for beginners, because the flow is fixed, the statements just come one after another. Right now, I have this: class SplittableBaseFormat: def parse(self): "Parses the body of the hand history, but first parse header if not yet parsed." if not self.header_parsed: self.parse_header() self._parse_table() self._parse_players() self._parse_button() self._parse_hero() self._parse_preflop() self._parse_street('flop') self._parse_street('turn') self._parse_street('river') self._parse_showdown() self._parse_pot() self._parse_board() self._parse_winners() self._parse_extra() self.parsed = True So the concrete parser need to define these methods in order in any way they want. Easy to follow, but takes longer to implement each individual concrete parser. So what about declarative? In this case Base classes (like SplittableFormat and XMLFormat) would do the heavy lifting based on regex and line/node number declarations in the concrete class, and concrete classes have no code at all, just line numbers and regexes, maybe other kind of rules. Like this: class SplittableFormat: def parse_table(): "Parses TABLE_REGEX and get information" # set attributes here def parse_players(): "parses PLAYER_REGEX and get information" # set attributes here class SpecificFormat1(SplittableFormat): TABLE_REGEX = re.compile('^(?P<table_name>.*) other info \d* etc') TABLE_LINE = 1 PLAYER_REGEX = re.compile('^Player \d: (?P<player_name>.*) has (.*) in chips.') PLAYER_LINE = 16 class SpecificFormat2(SplittableFormat): TABLE_REGEX = re.compile(r'^Tournament #(\d*) (?P<table_name>.*) other info2 \d* etc') TABLE_LINE = 2 PLAYER_REGEX = re.compile(r'^Seat \d: (?P<player_name>.*) has a stack of (\d*)') PLAYER_LINE = 14 So if I want to make it possible for non-developers to write these classes the way to go seems to be the declarative way, however, I'm almost certain I can't eliminate the declarations of regexes, which clearly needs (senior :D) programmers, so should I care about this at all? Do you think it matters to choose one over another or doesn't matter at all? Maybe if somebody wants to work on this project, they will, if not, no matter which idiom I choose. Can I "convert" non-programmers to help developing these? What are your observations? Other considerations: Imperative will allow any kind of work; there is a simple flow, which they can follow but inside that, they can do whatever they want. It would be harder to force a common interface with imperative because of this arbitrary implementations. Declarative will be much more rigid, which is a bad thing, because formats might change over time without any notice. Declarative will be harder for me to develop and takes longer time. Imperative is already ready to release. I hope a nice discussion will happen in this thread about programming idioms regarding which to use when, which is better for open source projects with different scenarios, which is better for wide range of developer skills. TL; DR: Parsing different file formats (plain text, XML) They contains same kind of information Target audience: non-developers, beginners Regex probably cannot be avoided 30-40 concrete parser classes needed Facilitate coding these concrete classes Which idiom is better?

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  • Interactive Data Language, IDL: Does anybody care?

    - by Alex
    Anyone use a language called Interactive Data Language, IDL? It is popular with scientists. I think it is a poor language because it is proprietary (every terminal running it has to have an expensive license purchased) and it has minimal support (try searching for IDL, the language, right now on stack) . I am trying to convince my colleagues to stop using it and learn C/C++/Python/Fortran/Java/Ruby. Does anybody know about or even care about IDL enough to have opinions on it? What do you think of it? Should I tell my colleagues to stop wasting their time on it now? How can I convince them? Edit: People are getting the impression that I don't know or use IDL. Also, I said IDL has minimal support which is true in one sense, so I must clarify that the scientific libraries are indeed large. I use IDL all the time, but this is exactly the problem: I am only using IDL because colleagues use it. There is a file format IDL uses, the .sav, which can only be opened in IDL. So I must use IDL to work with this data and transfer the data back to colleagues, but I know I would be more efficient in another language. This is like someone sending you a microsoft word file in an email attachment and if you don't understand how wrong that is then you probably write too many words not enough code and you bought microsoft word. Edit: As an alternative to IDL Python is popular. Here is a list of The Pros of IDL (and the cons) from AstroBetter: Pros of IDL Mature many numerical and astronomical libraries available Wide astronomical user base Numerical aspect well integrated with language itself Many local users with deep experience Faster for small arrays Easier installation Good, unified documentation Standard GUI run/debug tool (IDLDE) Single widget system (no angst about which to choose or learn) SAVE/RESTORE capability Use of keyword arguments as flags more convenient Cons of IDL Narrow applicability, not well suited to general programming Slower for large arrays Array functionality less powerful Table support poor Limited ability to extend using C or Fortran, such extensions hard to distribute and support Expensive, sometimes problem collaborating with others that don’t have or can’t afford licenses. Closed source (only RSI can fix bugs) Very awkward to integrate with IRAF tasks Memory management more awkward Single widget system (useless if working within another framework) Plotting: Awkward support for symbols and math text Many font systems, portability issues (v5.1 alleviates somewhat) not as flexible or as extensible plot windows not intrinsically interactive (e.g., pan & zoom) Pros of Python Very general and powerful programming language, yet easy to learn. Strong, but optional, Object Oriented programming support Very large user and developer community, very extensive and broad library base Very extensible with C, C++, or Fortran, portable distribution mechanisms available Free; non-restrictive license; Open Source Becoming the standard scripting language for astronomy Easy to use with IRAF tasks Basis of STScI application efforts More general array capabilities Faster for large arrays, better support for memory mapping Many books and on-line documentation resources available (for the language and its libraries) Better support for table structures Plotting framework (matplotlib) more extensible and general Better font support and portability (only one way to do it too) Usable within many windowing frameworks (GTK, Tk, WX, Qt…) Standard plotting functionality independent of framework used plots are embeddable within other GUIs more powerful image handling (multiple simultaneous LUTS, optional resampling/rescaling, alpha blending, etc) Support for many widget systems Strong local influence over capabilities being developed for Python Cons of Python More items to install separately Not as well accepted in astronomical community (but support clearly growing) Scientific libraries not as mature: Documentation not as complete, not as unified Not as deep in astronomical libraries and utilities Not all IDL numerical library functions have corresponding functionality in Python Some numeric constructs not quite as consistent with language (or slightly less convenient than IDL) Array indexing convention “backwards” Small array performance slower No standard GUI run/debug tool Support for many widget systems (angst regarding which to choose) Current lack of function equivalent to SAVE/RESTORE in IDL matplotlib does not yet have equivalents for all IDL 2-D plotting capability (e.g., surface plots) Use of keyword arguments used as flags less convenient Plotting: comparatively immature, still much development going on missing some plot type (e.g., surface) 3-d capability requires VTK (though matplotlib has some basic 3-d capability)

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  • Defend PHP; convince me it isn't horrible

    - by Jason L
    I made a tongue-in-cheek comment in another question thread calling PHP a terrible language and it got down-voted like crazy. Apparently there are lots of people here who love PHP. So I'm genuinely curious. What am I missing? What makes PHP a good language? Here are my reasons for disliking it: PHP has inconsistent naming of built-in and library functions. Predictable naming patterns are important in any design. PHP has inconsistent parameter ordering of built-in functions, eg array_map vs. array_filter which is annoying in the simple cases and raises all sorts of unexpected behaviour or worse. The PHP developers constantly deprecate built-in functions and lower-level functionality. A good example is when they deprecated pass-by-reference for functions. This created a nightmare for anyone doing, say, function callbacks. A lack of consideration in redesign. The above deprecation eliminated the ability to, in many cases, provide default keyword values for functions. They fixed this in PHP 5, but they deprecated the pass-by-reference in PHP 4! Poor execution of name spaces (formerly no name spaces at all). Now that name spaces exist, what do we use as the dereference character? Backslash! The character used universally for escaping, even in PHP! Overly-broad implicit type conversion leads to bugs. I have no problem with implicit conversions of, say, float to integer or back again. But PHP (last I checked) will happily attempt to magically convert an array to an integer. Poor recursion performance. Recursion is a fundamentally important tool for writing in any language; it can make complex algorithms far simpler. Poor support is inexcusable. Functions are case insensitive. I have no idea what they were thinking on this one. A programming language is a way to specify behavior to both a computer and a reader of the code without ambiguity. Case insensitivity introduces much ambiguity. PHP encourages (practically requires) a coupling of processing with presentation. Yes, you can write PHP that doesn't do so, but it's actually easier to write code in the incorrect (from a sound design perspective) manner. PHP performance is abysmal without caching. Does anyone sell a commercial caching product for PHP? Oh, look, the designers of PHP do. Worst of all, PHP convinces people that designing web applications is easy. And it does indeed make much of the effort involved much easier. But the fact is, designing a web application that is both secure and efficient is a very difficult task. By convincing so many to take up programming, PHP has taught an entire subgroup of programmers bad habits and bad design. It's given them access to capabilities that they lack the understanding to use safely. This has led to PHP's reputation as being insecure. (However, I will readily admit that PHP is no more or less secure than any other web programming language.) What is it that I'm missing about PHP? I'm seeing an organically-grown, poorly-managed mess of a language that's spawning poor programmers. So convince me otherwise!

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