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• Convincing why testing is good

  - by FireAphis

  Hello, In my team of real-time-embedded C/C++ developers, most people don't have any culture of testing their code beyond the casual manual sanity checks. I personally strongly believe in advantages of autonomous automatic tests, but when I try to convince I get some reappearing arguments like: We will spend more time on writing the tests than writing the code. It takes a lot of effort to maintain the tests. Our code is spaghetti; no way we can unit-test it. Our requirement are not sealed – we’ll have to rewrite all the tests every time the requirements are changed. Now, I'd gladly hear any convincing tips and advises, but what I am really looking for are references to researches, articles, books or serious surveys that show (preferably in numbers) how testing is worth the effort. Something like "We in IBM/Microsoft/Google, surveying 3475 active projects, found out that putting 50% more development time into testing decreased by 75% the time spent on fixing bugs" or "after half a year, the time needed to write code with test was only marginally longer than what used to take without tests". Any ideas? P.S.: I'm adding C++ tag too in case someone has a specific experience with convincing this, usually elitist, type of developers :-)

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• Working with fields which can mutate or be new instances altogether

  - by dotnetdev

  Structs are usually used for immutable data, eg a phone number, which does not mutate, but instead you get a new one (eg the number 000 becoming 0001 would mean two seperate numbers). However, pieces of information like Name, a string, can either mutate (company abc changing its name to abcdef, or being given a new name like def). For fields like this, I assume they should reside in the mutable class and not an immutable structure? My way of structuring code is to have an immutable concept, like Address (any change is a new address completely), in a struct and then reference it from a class like Customer, since Customer always has an address. So I would put CompanyName, or Employer, in the class as it is mutable. But a name can either mutate and so be the same 1 instance, or a new name setup and while the company still owning the first name too. Would the correct pattern for assigning a new instance (eg a new company name but the old name still owned by the company) be?: string name = ""; string newName = new string(); newName = "new"; name = newName; And a mutation just the standard assignment pattern? Thanks

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• Rand(); with exclusion to and already randomly generated number..?

  - by Stefan

  Hey, I have a function which calls a users associated users from a table. The function then uses the rand(); function to chose from the array 5 randomly selected userID's however!... In the case where a user doesnt have many associated users but above the min (if below the 5 it just returns the array as it is) then it gives bad results due to repeat rand numbers... How can overcome this or exclude a previously selected rand number from the next rand(); function call. Here is the section of code doing the work. Bare in mind this must be highly efficient as this script is used everywhere. $size = sizeof($users)-1; $nusers[0] = $users[rand(0,$size)]; $nusers[1] = $users[rand(0,$size)]; $nusers[2] = $users[rand(0,$size)]; $nusers[3] = $users[rand(0,$size)]; $nusers[4] = $users[rand(0,$size)]; return $nusers; Thanks in advance! Stefan

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• Check if date is allowed weekday in php?

  - by moogeek

  Hello! I'm stuck with a problem how to check if a specific date is within allowed weekdays array in php. For example, function dateIsAllowedWeekday($_date,$_allowed) { if ((isDate($_date)) && (($_allowed!="null") && ($_allowed!=null))){ $allowed_weekdays=json_decode($_allowed); $weekdays=array(); foreach($allowed_weekdays as $wd){ $weekday=date("l",date("w",strtotime($wd))); array_push($weekdays,$weekday); } if(in_array(date("l",strtotime($_date)),$weekdays)){return TRUE;} else {return FALSE;} } else {return FALSE;} } ///////////////////////////// $date="21.05.2010"; $wd="[0,1,2]"; if(dateIsAllowedWeekday($date,$wd)){echo "$date is within $wd weekday values!";} else{echo "$date isn't within $wd weekday values!"} I have input dates formatted as "d.m.Y" and an array returned from database with weekday numbers (formatted as 'Numeric representation of the day of the week') like [0,1,2] - (Sunday,Monday,Tuesday). The returned string from database can be "null", so i check it too. Them, the isDate function checks whether date is a date and it is ok. I want to check if my date, for example 21.05.2010 is an allowed weekday in this array. My function always returns TRUE and somehow weekday is always 'Thursday' and i don't know why... Is there any other ways to check this or what can be my error in the code above? thx

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• How to round a number to n decimal places in Java

  - by Alex Spurling

  What I'd like is a method to convert a double to a string which rounds using the half-up method. I.e. if the decimal to be rounded is a 5, it always rounds up the previous number. This is the standard method of rounding most people expect in most situations. I also would like only significant digits to be displayed. That is there should not be any trailing zeroes. I know one method of doing this is to use the String.format method: String.format("%.5g%n", 0.912385); returns: 0.91239 which is great, however it always displays numbers with 5 decimal places even if they are not significant: String.format("%.5g%n", 0.912300); returns: 0.91230 Another method is to use the DecimalFormatter: DecimalFormat df = new DecimalFormat("#.#####"); df.format(0.912385); returns: 0.91238 However as you can see this uses half-even rounding. That is it will round down if the previous digit is even. What I'd like is this: 0.912385 -> 0.91239 0.912300 -> 0.9123 What is the best way to achieve this in Java?

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• MySQL - What is wrong with this query or my database? Terrible performance.

  - by Moss

  SELECT * from `employees` a LEFT JOIN (SELECT phone1 p1, count(*) c, FROM `employees` GROUP BY phone1) b ON a.phone1 = b.p1; I'm not sure if it is this query in particular that has the problem. I have been getting terrible performance in general with this database. The table in question has 120,000 rows. I have tried this particular query remotely and locally with the MyISAM and InnoDB engines, with different types of joins, and with and without an index on phone1. I can get this to complete in about 4 minutes on a 10,000 row table successfully but performance drops exponentially with larger tables. Remotely it will lose connection to the server and locally it brings my system to its knees and seems to go on forever. This query is only a smaller step I was trying to do when a larger query couldn't complete. Maybe I should explain the whole scenario. I have one big flat ugly table that lists a bunch of people and their contact info and the info of the companies they work for. I'm trying to normalize the database and intelligently determine which phone numbers apply to individual people and which apply to an office location. My reasoning is that if a phone number occurs multiple times and the number of occurrence equals the number of times that the street address it is attached to occurs then it must be an office number. So the first step is to count each phone number grouping by phone number. Normally if you just use COUNT()...GROUP BY it will only list the first record it finds in that group so I figured I have to join the full table to the count table where the phone number matches. This does work but as I said I can't successfully complete it on any table much larger than 10,000 rows. This seems pathetic and this doesn't seem like a crazy query to do. Is there a better way to achieve what I want or do I have to break my large table into 12 pieces or is there something wrong with the table or db?

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• C# Homework - control structures (for, if)

  - by Freakingout

  I got a homework assignment today: "Create a program that calculates out how many ways you can add three numbers so that they equal 1000." I think this code should work, but it doesn't write out anything. using System; namespace ConsoleApp02 { class Program { public static void Main(string[] args) { for(int a = 0; a < 1000; a++) { for(int b = 0; b < 1000; b++) { for(int c = 0; c < 1000; c++) { for(int puls = a + b + c; puls < 1000; puls++) { if(puls == 1000) { Console.WriteLine("{0} + {1} + {2} = 1000", a, b, c); } } } } } Console.ReadKey(true); } } } What am I doing wrong? Any tips or solution?

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• using Python reduce over a list of pairs

  - by user248237

  I'm trying to pair together a bunch of elements in a list to create a final object, in a way that's analogous to making a sum of objects. I'm trying to use a simple variation on reduce where you consider a list of pairs rather than a flat list to do this. I want to do something along the lines of: nums = [1, 2, 3] reduce(lambda x, y: x + y, nums) except I'd like to add additional information to the sum that is specific to each element in the list of numbers nums. For example for each pair (a,b) in the list, run the sum as (a+b): nums = [(1, 0), (2, 5), (3, 10)] reduce(lambda x, y: (x[0]+x[1]) + (y[0]+y[1]), nums) This does not work: >>> reduce(lambda x, y: (x[0]+x[1]) + (y[0]+y[1]), nums) Traceback (most recent call last): File "<stdin>", line 1, in <module> File "<stdin>", line 1, in <lambda> TypeError: 'int' object is unsubscriptable Why does it not work? I know I can encode nums as a flat list - that is not the point - I just want to be able to create a reduce operation that can iterate over a list of pairs, or over two lists of the same length simultaneously and pool information from both lists. thanks.

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• Checkboxes in ADF are initially null, where I want them to be 0

  - by Mark Tielemans

  I am using ADF in JDeveloper and don´t have any experience with either of the two. Now I´ve run into quite some trouble yet, but for this particular thing I decided to consult the wisom of stackoverflow. The thing is, I have an edit form for an object that contains 3 checkboxes. The checked values are set to 1, unchecked to 0. In my database, the values are NOT NULL, and I want to keep it that way. The thing is, in the edit form, if the user submits the form leaving any boxes unchecked, it will result in an error, because the unchecked box values apparently remain null. Only after checking and then unchecking the boxes again, their values will be '0' rather than null. I've tried some things, including making the attributes mandatory in the domain BCD, but that just gives a bit more neat error message.. Any help would be greatly appreciated!! EDIT I made a little progress thanks to the guide provided by Joe, but still run into problems. I changed the values that should be checkboxes in my model, making them BOOLEANs where the table columns are NUMBERs (All are also mandatory and have a default value of 0). This automatically changed the corresponding View Object too. In the Application module, this now works great. It shows checkboxes, a checked one will return 1, an untouched one will return 0. However, I deleted the old form, and inserted a new one using the corresponding Data Control. I gave these values the checkbox type. I still had to edit the bindings (which I think reflects the problem, as this is not the case with, say, a model-level defined LOV) and gave them 1 for checked and 0 for unchecked. However, now apart from the original problem still occurring, also the checkboxes cannot be unchecked after checking, and return 0 when checked (and null when left untouched). Even though this has created new problems, it works correctly in my AM. Does someone know what I'm doing wrong in my Swing form?

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• Is there a recommended way to communicate scientific/engineering programming to C developers?

  - by ggkmath

  Hi, I have a lot of MATLAB code that needs to get ported to C (execution speed is critical for this work) as part of a back-end process for a web application. When I attempt to outsource this code to a C developer, I assume (correct me if I'm wrong) few C developers also understand MATLAB code (things like indexing and memory management are different, etc.). I wonder if there are any C developers out there that can recommend a procedure for me to follow to best communicate what the code does? For example, should I provide the MATLAB code and explain what it's doing line by line? Or, should I just provide the math/algorithm, explain it in plain English, and let the C developer implement it with this understanding in his/her own way (e.g. can I assume the developer understands how to work with complex math (i.e. imaginary numbers), how to generate histograms, perform an FFT, etc.)? Or, is there a better method? I expect I'm not the first to need to do this, so I wonder if any C developers out there ran into this situation and can share any conventional wisdom how they'd like this task to be transferred? Thanks in advance for any comments.

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• Why is it that an int in C++ that isnt initialized (then used) doesn't return an error?

  - by omizzle

  I am new to C++ (just starting). I come from a Java background and I was trying out the following piece of code that would sum the numbers between 1 and 10 (inclusive) and then print out the sum: /* * File: main.cpp * Author: omarestrella * * Created on June 7, 2010, 8:02 PM */ #include <cstdlib> #include <iostream> using namespace std; int main() { int sum; for(int x = 1; x <= 10; x++) { sum += x; } cout << "The sum is: " << sum << endl; return 0; } When I ran it it kept printing 32822 for the sum. I knew the answer was supposed to be 55 and realized that its print the max value for a short (32767) plus 55. Changing int sum; to int sum = 0; would work (as it should, since the variable needs to be initialized!). Why does this behavior happen, though? Why doesnt the compiler warn you about something like this? I know Java screams at you when something isnt initialized. Thank you.

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• Using stringstream instead of `sscanf` to parse a fixed-format string

  - by John Dibling

  I would like to use the facilities provided by stringstream to extract values from a fixed-format string as a type-safe alternative to sscanf. How can I do this? Consider the following specific use case. I have a std::string in the following fixed format: YYYYMMDDHHMMSSmmm Where: YYYY = 4 digits representing the year MM = 2 digits representing the month ('0' padded to 2 characters) DD = 2 digits representing the day ('0' padded to 2 characters) HH = 2 digits representing the hour ('0' padded to 2 characters) MM = 2 digits representing the minute ('0' padded to 2 characters) SS = 2 digits representing the second ('0' padded to 2 characters) mmm = 3 digits representing the milliseconds ('0' padded to 3 characters) Previously I was doing something along these lines: string s = "20101220110651184"; unsigned year = 0, month = 0, day = 0, hour = 0, minute = 0, second = 0, milli = 0; sscanf(s.c_str(), "%4u%2u%2u%2u%2u%2u%3u", &year, &month, &day, &hour, &minute, &second, &milli ); The width values are magic numbers, and that's ok. I'd like to use streams to extract these values and convert them to unsigneds in the interest of type safety. But when I try this: stringstream ss; ss << "20101220110651184"; ss >> setw(4) >> year; year retains the value 0. It should be 2010. How do I do what I'm trying to do? I can't use Boost or any other 3rd party library, nor can I use C++0x.

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• Ruby: counters, counting and incrementing

  - by Shyam

  Hi, If you have seen my previous questions, you'd already know I am a big nuby when it comes to Ruby. So, I discovered this website which is intended for C programming, but I thought whatever one can do in C, must be possible in Ruby (and more readable too). The challenge is to print out a bunch of numbers. I discovered this nifty method .upto() and I used a block (and actually understanding its purpose). However, in IRb, I got some unexpected behavior. class MyCounter def run 1.upto(10) { |x| print x.to_s + " " } end end irb(main):033:0> q = MyCounter.new => #<MyCounter:0x5dca0> irb(main):034:0> q.run 1 2 3 4 5 6 7 8 9 10 => 1 I have no idea where the = 1 comes from :S Should I do this otherwise? I am expecting to have this result: 1 2 3 4 5 6 7 8 9 10 Thank you for your answers, comments and feedback!

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• Working with a list, performing arithmetic logic in Python

  - by haea ohoh

  Suppose I have made a large list of numbers, and I want to make another one which I will add, pairwise, with the first list. Here's the first list, A: [109, 77, 57, 34, 94, 68, 96, 72, 39, 67, 49, 71, 121, 89, 61, 84, 45, 40, 104, 68, 54, 60, 68, 62, 91, 45, 41, 118, 44, 35, 53, 86, 41, 63, 111, 112, 54, 34, 52, 72, 111, 113, 47, 91, 107, 114, 105, 91, 57, 86, 32, 109, 84, 85, 114, 48, 105, 109, 68, 57, 78, 111, 64, 55, 97, 85, 40, 100, 74, 34, 94, 78, 57, 77, 94, 46, 95, 60, 42, 44, 68, 89, 113, 66, 112, 60, 40, 110, 89, 105, 113, 90, 73, 44, 39, 55, 108, 110, 64, 108] And here's B: [35, 106, 55, 61, 81, 109, 82, 85, 71, 55, 59, 38, 112, 92, 59, 37, 46, 55, 89, 63, 73, 119, 70, 76, 100, 49, 117, 77, 37, 62, 65, 115, 93, 34, 107, 102, 91, 58, 82, 119, 75, 117, 34, 112, 121, 58, 79, 69, 68, 72, 110, 43, 111, 51, 102, 39, 52, 62, 75, 118, 62, 46, 74, 77, 82, 81, 36, 87, 80, 56, 47, 41, 92, 102, 101, 66, 109, 108, 97, 49, 72, 74, 93, 114, 55, 116, 66, 93, 56, 56, 93, 99, 96, 115, 93, 111, 57, 105, 35, 99] How might I generate the arithmatic addition logic, processing each pairwise value one by one (A[0] and B[0], through A[99], B[99]) and producing the list C (A[0] + B[0] through A[99]+ B[99])?

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• Algorithm to pick values from set to match target value?

  - by CSharperWithJava

  I have a fixed array of constant integer values about 300 items long (Set A). The goal of the algorithm is to pick two numbers (X and Y) from this array that fit several criteria based on input R. Formal requirement: Pick values X and Y from set A such that the expression X*Y/(X+Y) is as close as possible to R. That's all there is to it. I need a simple algorithm that will do that. Additional info: The Set A can be ordered or stored in any way, it will be hard coded eventually. Also, with a little bit of math, it can be shown that the best Y for a given X is the closest value in Set A to the expression X*R/(X-R). Also, X and Y will always be greater than R From this, I get a simple iterative algorithm that works ok: int minX = 100000000; int minY = 100000000; foreach X in A if(X<=R) continue; else Y=X*R/(X-R) Y=FindNearestIn(A, Y);//do search to find closest useable Y value in A if( X*Y/(X+Y) < minX*minY/(minX+minY) ) then minX = X; minY = Y; end end end I'm looking for a slightly more elegant approach than this brute force method. Suggestions?

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• Displaying performance metrics in a modern web app?

  - by Charles

  We're updating our ancient internal PHP application at work. Right now, we gather extensive performance measurements on every pageview, and log them to the database. Additionally, users requested that some of the metrics be displayed at the bottom of the page. This worked out pretty well for us, because the last thing that the application does on every request is include the file containing the HTML footer. The updated parts of the application use an MVC framework and a Dispatch/Request/Response loop. The page footer is no longer the last thing done. In fact, it could very well be the first thing done, before the rest of the page is created. Because we can grab the Response before it's returned to the user, we could try to include placeholders for the performance metrics in the footer and simply replace them with the actual numbers, but this strikes me as a bad idea somehow. How do you handle this in your modern web app? While we're using PHP, I'm curious how it's done in a Ruby/Rails app, and in your favorite Python framework.

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• iPhone or Android apps that use SMS based authentication?

  - by JSW

  What are some iPhone or Android applications that use SMS as their primary means of user authentication? I'm interested to see such apps in action. SMS-auth seems like a natural approach that is well-situated to mobile contexts. The basic workflow is: to sign up, a user provides a phone number; the app calls a backend webservice which generates a signed URL and sends it to the phone number via an SMS gateway; the user receives the SMS, clicks the link, and is thus verified and logged in. This results in a very strong user identity that is difficult to spoof yet fairly easy. It can be paired with a username or additional account attributes as needed for the product requirements. Despite the advantages, this does not seem to be in much use - hence my question. My initial assumption is that this is because products and users are wary of asking for / providing phone numbers, which users consider sensitive information. That said, I hope this becomes an increasingly more commonplace approach.

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• Project Euler, Problem 10 java solution now working

  - by Dennis S

  Hi, I'm trying to find the sum of the prime numbers < 2'000'000. This is my solution in java but I can't seem get the correct answer. Please give some input on what could be wrong and general advice on the code is appreciated. Printing 'sum' gives: 1308111344, which is incorrect. /* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ class Helper{ public void run(){ Integer sum = 0; for(int i = 2; i < 2000000; i++){ if(isPrime(i)) sum += i; } System.out.println(sum); } private boolean isPrime(int nr){ if(nr == 2) return true; else if(nr == 1) return false; if(nr % 2 == 0) return false; for(int i = 3; i < Math.sqrt(nr); i += 2){ if(nr % i == 0) return false; } return true; } } class Problem{ public static void main(String[] args){ Helper p = new Helper(); p.run(); } }

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• What's the correct terminology for something that isn't quite classification nor regression?

  - by TC

  Let's say that I have a problem that is basicly classification. That is, given some input and a number of possible output classes, find the correct class for the given input. Neural networks and decision trees are some of the algorithms that may be used to solve such problems. These algorithms typically only emit a single result however: the resulting classification. Now what if I weren't only interested in one classification, but in the posterior probabilities that the input belongs to each of the classes. I.E., instead of the answer "This input belongs in class A", I want the answer "This input belongs to class A with 80%, class B with 15% and class C with 5%". My question is not on how to obtain these posterior probabilities, but rather on the correct terminology to describe the process of finding them. You could call it regression, since we are now trying to estimate a number of real valued numbers, but I am not quite sure if that's right. I feel it's not exactly classification either, it's something in between the two. Is there a word that describes the process of finding the class conditional posterior probabilities that some input belongs in each of the possible output classes? P.S. I'm not exactly sure if this question is enough of a programming question, but since it's about machine learning and machine learning generally involves a decent amount of programming, let's give it a shot.

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• Cross-browser method for getting width and height of a DIV?

  - by thinkthank

  This is my first post, so please go easy on me. I'm sure I'm doing everything wrong. However, I couldn't find any posts that answered the question above. I use jQuery. I'm trying to find a way to get the current width and height of a DIV element, even if they're set to "auto". I've found many ways to do this, but no method returns the same width in IE. It is important that this method is cross-browser, as it will break the layout of the page if different numbers are returned in different browsers. .width() and .height() do not work because in IE, padding is subtracted (e.g. width() returns 25 where width is 30 and padding is 5). .outerWidth() and .outerHeight() are not consistent either. While they work IE (believe it or not) in FF, the padding is added again to the full width (e.g. outerWidth() returns 110 in FF where width is 100px and padding is 10px). Is there any way out of this mess without writing complex browser checks? Thanks!

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• Cannot display converted value inside xml field

  - by zurna

  PS: My bad, there was not an error. I forgot to upload the latest version to the server... I have multimedias and images table. I save images in multimedias table with their images table id numbers. Then whenever I need image's url, with a simple function I get it from images table. The problem I am having is when I try to display image's url inside ImageURL, it just does not happen. This is very annoying. xml output <?xml version='1.0' encoding='windows-1254' ?> <rows><row id='1'> <MultimediaTitle>Hagi Goals</MultimediaTitle> /FLPM/media/images/5Y2K4T5V_sm.jpg <ImageURL><![CDATA[]]></ImageURL> <Videos> <VideoID id='1'><VideoURL>/FLPM/media/videos/0H7T9C0F.flv</VideoURL></VideoID> <VideoID id='2'><VideoURL>/FLPM/media/videos/9L6X9G9J.flv</VideoURL></VideoID> </Videos> </row> </rows>

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• [FIXED] Scan file contents into an array of a structure.

  - by ZaZu

  Hello, I have a structure in my program that contains a particular array. I want to scan a random file with numbers and put the contents into that array. This is my code : ( NOTE : This is a sample from a bigger program, so I need the structure and arrays as declared ) The contents of the file are basically : 5 4 3 2 5 3 4 2 #include<stdio.h> #define first 500 #define sec 500 struct trial{ int f; int r; float what[first][sec]; }; int trialtest(trial *test); main(){ trial test; trialtest(&test); } int trialtest(trial *test){ int z,x,i; FILE *fin; fin=fopen("randomfile.txt","r"); for(i=0;i<5;i++){ fscanf(fin,"%5.2f\t",(*test).what[z][x]); } fclose(fin); return 0; } But the problem is, whenever this I run this code, I get this error : (25) : warning 508 - Data of type 'double' supplied where a pointer is required I tried adding do{ for(i=0;i<5;i++){ q=fscanf(fin,"%5.2f\t",(*test).what[z][x]); } }while(q!=EOF); But that didnt work either, it gives the same error. Does anyone have a solution to this problem ?

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• HMAC URLs instead of login?

  - by Tres

  In implementing my site (a Rails site if it makes any difference), one of my design priorities is to relieve the user of the need to create yet another username and password while still providing useful per-user functionality. The way I am planning to do this is: User enters information on the site. Information is associated with the user via server-side session. User completes entering information, server sends an access URL via e-mail to the user roughly in the form of: http://siteurl/<user identifier>/<signature: HMAC(secret + salt + user identifier)> User clicks URL, site looks up user ID and salt and computes the HMAC with the server-stored secret and authenticates if the computed HMAC and signature match. My question is: is this a reasonably secure way to accomplish what I'm looking to do? Are there common attacks that would render it useless? Is there a compelling reason to abandon my desire to avoid a username/password? Is there a must-read book or article on the subject? Note that I'm not dealing with credit card numbers or anything exceedingly private, but I would still like to keep the information reasonably secure.

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• Template trick to optimize out allocations

  - by anon

  I have: struct DoubleVec { std::vector<double> data; }; DoubleVec operator+(const DoubleVec& lhs, const DoubleVec& rhs) { DoubleVec ans(lhs.size()); for(int i = 0; i < lhs.size(); ++i) { ans[i] = lhs[i]] + rhs[i]; // assume lhs.size() == rhs.size() } return ans; } DoubleVec someFunc(DoubleVec a, DoubleVec b, DoubleVec c, DoubleVec d) { DoubleVec ans = a + b + c + d; } Now, in the above, the "a + b + c + d" will cause the creation of 3 temporary DoubleVec's -- is there a way to optimize this away with some type of template magic ... i.e. to optimize it down to something equivalent to: DoubleVec ans(a.size()); for(int i = 0; i < ans.size(); i++) ans[i] = a[i] + b[i] + c[i] + d[i]; You can assume all DoubleVec's have the same # of elements. The high level idea is to have do some type of templateied magic on "+", which "delays the computation" until the =, at which point it looks into itself, goes hmm ... I'm just adding thes numbers, and syntheizes a[i] + b[i] + c[i] + d[i] ... instead of all the temporaries. Thanks!

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• Listening UDP or switch to TCP in a MFC application

  - by Alexander.S

  I'm editing a legacy MFC application, and I have to add some basic network functionalities. The operating side has to receive a simple instruction (numbers 1,2,3,4...) and do something based on that. The clients wants the latency to be as fast as possible, so naturally I decided to use datagrams (UDP). But reading all sorts of resources left me bugged. I cannot listen to UDP sockets (CAsyncSocket) in MFC, it's only possible to call Receive which blocks and waits. Blocking the UI isn't really a smart. So I guess I could use some threading technique, but since I'm not all that experienced with MFC how should that be implemented? The other part of the question is should I do this, or revert to TCP, considering reliability and implementation issues. I know that UDP is unreliable, but just how unreliable is it really? I read that it is up to 50% faster, which is a lot for me. References I used: http://msdn.microsoft.com/en-us/library/09dd1ycd(v=vs.80).aspx

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