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  • How can I make sure that I'm actually learning how to program rather than simply learning the details of a language?

    - by Ryan
    I often hear that a real programmer can easily learn any language within a week. Languages are just tools for getting things done, I'm told. Programming is the ultimate skill that must be learned and mastered. How can I make sure that I'm actually learning how to program rather than simply learning the details of a language? And how can I develop programming skills that can be applied towards all languages instead of just one?

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  • Why not expose a primary key

    - by Angelo Neuschitzer
    In my education I have been told that it is a flawed idea to expose actual primary keys (not only DB keys, but all primary accessors) to the user. I always thought it to be a security problem (because an attacker could attempt to read stuff not their own). Now I have to check if the user is allowed to access anyway, so is there a different reason behind it? Also, as my users have to access the data anyway I will need to have a public key for the outside world somewhere in between. Now that public key has the same problems as the primary key, doesn't it?

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  • Quality Assurance activities

    - by MasloIed
    Having asked but deleted the question as it was a bit misunderstood. If Quality Control is the actual testing, what are the commonest true quality assurance activities? I have read that verification (reviews, inspections..) but it does not make much sense to me as it looks more like quality control as mentioned here: DEPARTMENT OF HEALTH AND HUMAN SERVICES ENTERPRISE PERFORMANCE LIFE CYCLE FRAMEWORK Practices guide Verification - “Are we building the product right?” Verification is a quality control technique that is used to evaluate the system or its components to determine whether or not the project’s products satisfy defined requirements. During verification, the project’s processes are reviewed and examined by members of the IV&V team with the goal of preventing omissions, spotting problems, and ensuring the product is being developed correctly. Some Verification activities may include items such as: • Verification of requirement against defined specifications • Verification of design against defined specifications • Verification of product code against defined standards • Verification of terms, conditions, payment, etc., against contracts

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  • bug: deviation from requirements vs deviation from expectations

    - by user970696
    I am not clear on this one. No matter the terminology, in the end the software fault/bug causes (according to a lot of sources): Deviation from requirements Devation from expectations But if the expectations are not in requirements, then stakeholder could see a bug everywhere as he expected it to be like this or that..So how can I really know? I did read that specification can miss things and then of course its expected but not specified (by mistake).

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  • Is verification and validation part of testing process?

    - by user970696
    Based on many sources I do not believe the simple definition that aim of testing is to find as many bugs as possible - we test to ensure that it works or that it does not. E.g. followint are goals of testing form ISTQB: Determine that (software products) satisfy specified requirements ( I think its verificication) Demonstrate that (software products) are fit for purpose (I think that is validation) Detect defects I would agree that testing is verification, validation and defect detection. Is that correct?

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  • How often do CPUs make calculation errors?

    - by veryfoolish
    In Dijkstra's Notes on Structured Programming he talks a lot about the provability of computer programs as abstract entities. As a corollary, he remarks how testing isn't enough. E.g., he points out the fact that it would be impossible to test a multiplication function f(x,y) = x*y for any large values of x and y across the entire ranges of x and y. My question concerns his misc. remarks on "lousy hardware". I know the essay was written in the 1970s when computer hardware was less reliable, but computers still aren't perfect, so they must make calculation mistakes sometimes. Does anybody know how often this happens or if there are any statistics on this?

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  • I don't understand why algorithms are so special

    - by Jessica
    I'm a student of computer science trying to soak up as much information on the topic as I can during my free time. I keep returning to algorithms time and again in various formats (online course, book, web tutorial), but the concept fails to sustain my attention. I just don't understand: why are algorithms so special? I can tell you why fractals are awesome, why the golden ratio is awesome, why origami is awesome and scientific applications of all the above. Heck I even love Newton's laws and conical sections. But when it comes to algorithms, I'm just not astounded. They are not insightful in new ways about human cognition at all. I was expecting algorithms to be shattering preconceptions and mind-altering but time and time again they fail miserably. What am I doing wrong in my approach? Can someone tell me why algorithms are so awesome?

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  • Is there a real difference between dynamic analysis and testing?

    - by user970696
    Often testing is regarded as a dynamic analysis of a software. Yet while writing my thesis, the reviewer noted to me that dynamic analysis is about analyzing the program behind the scenes - e.g. profiling and that it is not the same as testing because its "analysis" which looks inside and observes. I know that "static analysis" is not testing, should we then separate this "dynamic analysis" also from testing? Some books do refer to dynamic analysis in this sense. I would maybe say that testing is a one mean of dynamic analysis?

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  • What are the processes of true Quality assurance?

    - by user970696
    Having read that Quality Assurance (QA) is focused on processes (while Quality Control (QC) is focused on the product), the books often mentions QA is the verification process - doing peer reviews, inspections etc. I still tend to think these are also QC as they check intermediate products. Elsewhere I have read that QA activity is e.g. choosing the right bugtracker. That sounds better to me in terms of process improvement. The question that close-voting person obviously missed is pretty clear: What are the activities that true QA should perform? I would appreciate the reference as I work on my thesis dealing with all these discrepancies and inconsistencies in the software quality world.

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  • Is ORM an Anti-Pattern?

    - by derphil
    I had a very stimulating and interessting discussion with a colleague about ORM and it's Pros and Cons. In my opinion, an ORM is useful only in the rarest cases. At least in my experience. But I don't want to list my own arguments at this time. So I ask you, what do you think about ORM? What are the Pros and the Cons? P.S. I've posted this "question" yesterday on Stackoverflow, but some of the user think, that this should better posted here.

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  • Verfication vs validation again, does testing belong to verification? If so, which?

    - by user970696
    I have asked before and created a lot of controversy so I tried to collect some data and ask similar question again. E.g. V&V where all testing is only validation: http://www.buzzle.com/editorials/4-5-2005-68117.asp According to ISO 12207, testing is done in validation: •Prepare Test Requirements,Cases and Specifications •Conduct the Tests In verification, it mentiones. The code implements proper event sequence, consistent interfaces, correct data and control flow, completeness, appropriate allocation timing and sizing budgets, and error definition, isolation, and recovery. and The software components and units of each software item have been completely and correctly integrated into the software item Not sure how to verify without testing but it is not there as a technique. From IEEE: Verification: The process of evaluating software to determine whether the products of a given development phase satisfy the conditions imposed at the start of that phase. [IEEE-STD-610]. Validation: The process of evaluating software during or at the end of the development process to determine whether it satisfies specified requirements. [IEEE-STD-610] At the end of development phase? That would mean UAT.. So the question is, what testing (unit, integration, system, uat) will be considered verification or validation? I do not understand why some say dynamic verification is testing, while others that only validation. An example: I am testing an application. System requirements say there are two fields with max. lenght of 64 characters and Save button. Use case say: User will fill in first and last name and save. When checking the fields and Save button presence, I would say its verification. When I follow the use case, its validation. So its both together, done on the system as a whole.

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  • Functional testing in the verification

    - by user970696
    Yesterday my question How come verification does not include actual testing? created a lot of controversy, yet did not reveal the answer for related and very important question: does black box functional testing done by testers belong to verification or validation? ISO 12207:12208 here mentiones testing explicitly only as a validation activity, however, it speaks about validation of requirements of the intended use. For me its more high level, like UAT test cases written by business users ISO mentioned above does not mention any specific verification (7.2.4.3.2)except for Requirement verification, Design verification, Document and Code & Integration verification. The last two can be probably thought as unit and integrated testing. But where is then the regular testing done by testers at the end of the phase? The book I mentioned in the original question mentiones that verification is done by static techniques, yet on the V model graph it describes System testing against high level description as a verification, mentioning it includes all kinds of testing like functional, load etc. In the IEEE standard for V&V, you can read this: Even though the tests and evaluations are not part of the V&V processes, the techniques described in this standard may be useful in performing them. So that is different than in ISO, where validation mentiones testing as the activity. Not to mention a lot of contradicting information on the net. I would really appreciate a reference to e.g. a standard in the answer or explanation of what I missed in the ISO. For me, I am unable to tell where the testers work belong.

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  • How many copies are needed to enlarge an array?

    - by user10326
    I am reading an analysis on dynamic arrays (from the Skiena's algorithm manual). I.e. when we have an array structure and each time we are out of space we allocate a new array of double the size of the original. It describes the waste that occurs when the array has to be resized. It says that (n/2)+1 through n will be moved at most once or not at all. This is clear. Then by describing that half the elements move once, a quarter of the elements twice, and so on, the total number of movements M is given by: This seems to me that it adds more copies than actually happen. E.g. if we have the following: array of 1 element +--+ |a | +--+ double the array (2 elements) +--++--+ |a ||b | +--++--+ double the array (4 elements) +--++--++--++--+ |a ||b ||c ||c | +--++--++--++--+ double the array (8 elements) +--++--++--++--++--++--++--++--+ |a ||b ||c ||c ||x ||x ||x ||x | +--++--++--++--++--++--++--++--+ double the array (16 elements) +--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--+ |a ||b ||c ||c ||x ||x ||x ||x || || || || || || || || | +--++--++--++--++--++--++--++--++--++--++--++--++--++--++--++--+ We have the x element copied 4 times, c element copied 4 times, b element copied 4 times and a element copied 5 times so total is 4+4+4+5 = 17 copies/movements. But according to formula we should have 1*(16/2)+2*(16/4)+3*(16/8)+4*(16/16)= 8+8+6+4=26 copies of elements for the enlargement of the array to 16 elements. Is this some mistake or the aim of the formula is to provide a rough upper limit approximation? Or am I missunderstanding something here?

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  • How does the "Fourth Dimension" work with arrays?

    - by Questionmark
    Abstract: So, as I understand it (although I have a very limited understanding), there are three dimensions that we (usually) work with physically: The 1st would be represented by a line. The 2nd would be represented by a square. The 3rd would be represented by a cube. Simple enough until we get to the 4th -- It is kinda hard to draw in a 3D space, if you know what I mean... Some people say that it has something to do with time. The Question: Now, that is all great with me. My question isn't about this, or I'd be asking it on MathSO or PhysicsSO. My question is: How does the computer handle this with arrays? I know that you can create 4D, 5D, 6D, etc... arrays in many different programming languages, but I want to know how that works.

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  • Severity and relation to occurence - priority?

    - by user970696
    I have been browsing through some webpages related to testing and found one dealing with the metrics of testing. It says: The severity level of a defect indicates the potential business impact for the end user (business impact = effect on the end user x frequency of occurrence). I do not think think this is correct or what am I missing? Usually it is the priority which is the result of such a calculation (severe bug that occurs rarely is still severe but does not have to be fixed immediately). Also from this description, what is the difference between the effect on the end user and business impact?

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  • Is excessive indirection and/or redundant encapsulation a recognized concept?

    - by Omega
    I'm curious if there's a series of tendencies or anti-patterns when programming whereby a developer will always locally re-wrap external dependencies when consuming them. A slightly less vague example might be say when consuming an implementation of an interface or abstract, and mapping every touch-point locally before interacting with them. Like an overcomplicated take on composition. Given my example, would the interface not be reliable enough and any change to it never be surmountable any any level of indirection? Is this a good or a bad practice? Can it ever go too far? Does it have a proper name?

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  • Quality Assurance tools discrepancies

    - by Roudak
    It is a bit ironic, yesterday I answered a question related to this topic that was marked to be good and today I'm the one who asks. These are my thoughts and a question: Also let's agree on the terms: QA is a set of activities that defines and implements processes during SW development. The common tool is the process audit. However, my colleague at work agrees with the opinion that reviews and inspections are also quality assurance tools, although most sources classify them as quality control. I would say both sides are partially right: during inspections, we evaluate a physical product (clearly QC) but we see it as a white box so we can check its compliance with set processes (QA). Do you think it is the reason of the dichotomy among the authors? I know it is more like an academic question but it deserves the answer :)

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  • Isn't class scope purely for organization?

    - by Di-0xide
    Isn't scope just a way to organize classes, preventing outside code from accessing certain things you don't want accessed? More specifically, is there any functional gain to having public, protected, or private-scoped methods? Is there any advantage to classifying method/property scope rather than to, say, just public-ize everything? My presumption says no simply because, in binary code, there is no sense of scope (other than r/w/e, which isn't really scope at all, but rather global permissions for a block of memory). Is this correct? What about in languages like Java and C#[.NET]?

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  • ISO 12207 - testing being only validation activity? [closed]

    - by user970696
    Possible Duplicate: How come verification does not include actual testing? ISO norm 12207 states that testing is only validation activity, while all static inspections are verification (that requirement, code.. is complete, correct..). I did found some articles saying its not correct but you know, it is not "official". I would like to understand because there are two different concepts (in books & articles): 1) Verification is all testing except for UAT (because only user can really validate the use). E.g. here OR 2) Verification is everything but testing. All testing is validation. E.g. here Definitions are mostly the same, as Sommerville's: The aim of verification is to check that the software meets its stated functional and non-functional requirements. Validation, however, is a more general process. The aim of validation is to ensure that the software meets the customer’s expectations. It goes beyond simply checking conformance with the specification to demonstrating that the software does what the customer expects it to do It is really bugging me because I tend to agree that functional testing done on a product (SIT) is still verification because I just follow the requirements. But ISO does not agree..

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  • How often do CPUs make calculation errors?

    - by veryfoolish
    In Dijkstra's Notes on Structured Programming he talks a lot about the provability of computer programs as abstract entities. As a corollary, he remarks how testing isn't enough. E.g., he points out the fact that it would be impossible to test a multiplication function f(x,y) = x*y for any large values of x and y across the entire ranges of x and y. My question concerns his misc. remarks on "lousy hardware". I know the essay was written in the 1970s when computer hardware was less reliable, but computers still aren't perfect, so they must make calculation mistakes sometimes. Does anybody know how often this happens or if there are any statistics on this?

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  • Semantic algorithms

    - by Mythago
    I have a more theoretical than practical question. I'll start with an example - when I get an email and open it on my iPad, there is a feature, which recognizes the timestamp from the text and offers me to create an event in the calendar. Simply told, I want to know theoretically how it's done - I believe it's some kind of semantic parsing, and I would like if someone could point me to some resources, where I can read more about this.

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  • What is the aim of software testing?

    - by user970696
    Having read many books, there is a basic contradiction: Some say, "the goal of testing is to find bugs" while other say "the goal of the testing is to equalize the quality of the product", meaning that bugs are its by-products. I would also agree that if testing would be aimed primarily on a bug hunt, who would do the actual verification and actually provided the information, that the software is ready? Even e.g. Kaner changed his original definiton of testing goal from bug hunting to quality assesement provision but I still cannot see the clear difference. I percieve both as equally important. I can verify software by its specification to make sure it works and in that case, bugs found are just by products. But also I perform tests just to brake things. Also what definition is more accurate?

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  • Come up with a real-world problem in which only the best solution will do (a problem from Introduction to algorithms) [closed]

    - by Mike
    EDITED (I realized that the question certainly needs a context) The problem 1.1-5 in the book of Thomas Cormen et al Introduction to algorithms is: "Come up with a real-world problem in which only the best solution will do. Then come up with one in which a solution that is “approximately” the best is good enough." I'm interested in its first statement. And (from my understanding) it is asked to name a real-world problem where only the exact solution will work as opposed to a real-world problem where good-enough solution will be ok. So what is the difference between the exact and good enough solution. Consider some physics problem for example the simulation of the fulid flow in the permeable medium. To make this simulation happen some simplyfing assumptions have to be made when deriving a mathematical model. Otherwise the model becomes at least complex and unsolvable. Virtually any particle in the universe has its influence on the fluid flow. But not all particles are equal. Those that form the permeable medium are much more influental than the ones located light years away. Then when the mathematical model needs to be solved an exact solution can rarely be found unless the mathematical model is simple enough (wich probably means the model isn't close to reality). We take an approximate numerical method and after hours of coding and days of verification come up with the program or algorithm which is a solution. And if the model and an algorithm give results close to a real problem by some degree that is good enough soultion. Its worth noting the difference between exact solution algorithm and exact computation result. When considering real-world problems and real-world computation machines I believe all physical problems solutions where any calculations are taken can not be exact because universal physical constants are represented approximately in the computer. Any numbers are represented with the limited precision, at least limited by amount of memory available to computing machine. I can imagine plenty of problems where good-enough, good to some degree solution will work, like train scheduling, automated trading, satellite orbit calculation, health care expert systems. In that cases exact solutions can't be derived due to constraints on computation time, limitations in computer memory or due to the nature of problems. I googled this question and like what this guy suggests: there're kinds of mathematical problems that need exact solutions (little note here: because the question is taken from the book "Introduction to algorithms" the term "solution" means an algorithm or a program, which in this case gives exact answer on each input). But that's probably more of theoretical interest. So I would like to narrow down the question to: What are the real-world practical problems where only the best (exact) solution algorithm or program will do (but not the good-enough solution)? There are problems like breaking of cryptographic ciphers where only exact solution matters in practice and again in practice the process of deciphering without knowing a secret should take reasonable amount of time. Returning to the original question this is the problem where good-enough (fast-enough) solution will do there's no practical need in instant crack though it's desired. So the quality of "best" can be understood in any sense: exact, fastest, requiring least memory, having minimal possible network traffic etc. And still I want this question to be theoretical if possible. In a sense that there may be example of computer X that has limited resource R of amount Y where the best solution to problem P is the one that takes not more than available Y for inputs of size N*Y. But that's the problem of finding solution for P on computer X which is... well, good enough. My final thought that we live in a world where it is required from programming solutions to practical purposes to be good enough. In rare cases really very very good but still not the best ones. Isn't it? :) If it's not can you provide an example? Or can you name any such unsolved problem of practical interest?

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  • Considerations for changing URL path

    - by Mandar
    I am having an e-commerce site and current URL structure is like this: www.example.com/category1 [Category landing page] www.example.com/category1/sub-category [sub-category listing page] www.example.com/category1/sub-category/product-name [Product Details page] I am finding it difficult to identify from the URLs whether the URL is category landing page or a listing page or a product details page (primarily in Google Analytics). To solve this problem, I am thinking of adding qualifiers in the URL as follows: www.example.com/category1/cat-land [Category landing page] www.example.com/category1/sub-category/cat-list [sub-category listing page] www.example.com/category1/sub-category/product-name/prod-details [Product Details page] Original URLs would be redirected to new URLs using 301 permanent redirect. Would this have any negative effect on existing SEO and Google ranking?

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  • Validation and Verification explanation (Boehm) - I cannot understand its point

    - by user970696
    Hopefully my last thread about V&V as I found the B.Boehm is text which I just do not understand well (likely my technical English is not that good). http://csse.usc.edu/csse/TECHRPTS/1979/usccse79-501/usccse79-501.pdf Basically he says that verification is about checking that products derived from requirements baseline must correspond to it and that deviation leads only to changes in these derived products (design, code). But he says it begins with design and ends with acceptance tests (you can check the V model inside). The thing is, I have accepted ISO12207 in terms of all testing is validation, yet it does not make any sense here. In order to be sure the product complies with requirements (acceptance test) I need to test it. Also it says that validation problems means that requirements are bad and needs to be changed - which does not happen with testing that testers do, who just checks correspondence with requirements.

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