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  • Do I correctly understand what a class is?

    - by Matt
    I've had trouble finding a clear, concise laymans definition of a class. Usually, they give general ideas without specifically spelling it out, and I'm wondering if I'm understanding this correctly. As I understand it, a class is the set of code that controls an object. For example, in an app that has a button for 'Yes' and a button for 'No', and a text box for output, the code that tells the computer what to do when the user uses the Yes button is one class, the code for hitting No is another class, and an object is the two buttons and what they do together to influence the output box. Am I right, or am I confusing terms here? Thanks

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  • GoTo statements, and alternatives (help me please im new) (VB.net)

    - by qais
    Basically I posted a code snippet on a forum asking for help and people pointed out to me that using GoTo statements is very bad programming practise so I'm just wondering, why is it bad? And also what alternative is there to use, like for example in this program ive done for homework the user has to input their date of birth and if the month/date/year are invalid or unrealistic(using if statements checking the integer inputs size, if theres any better way to do this i'd appreciate if you could tell me that also :D) then how would i be able to loop back to ask them again? heres a little extract of my code retryday: Console.WriteLine("Please enter the day you were born : ") day = Console.ReadLine If day > 31 Or day < 1 Then Console.WriteLine("Please enter a valid day") GoTo retryday End If

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  • Why do I not get the correct answer for Euler 56 in J?

    - by Gregory Higley
    I've solved 84 of the Project Euler problems, mostly in Haskell. I am now going back and trying to solve in J some of those I already solved in Haskell, as an exercise in learning J. Currently, I am trying to solve Problem 56. Let me stress that I already know what the right answer is, since I've already solved it in Haskell. It's a very easy, trivial problem. I will not give the answer here. Here is my solution in J: digits =: ("."0)":"0 eachDigit =: adverb : 'u@:digits"0' NB. I use this so often I made it an adverb. cartesian =: adverb : '((#~ #) u ($~ ([:*~#)))' >./ +/ eachDigit x: ^ cartesian : i. 99 This produces a number less than the desired result. In other words, it's wrong somehow. Any J-ers out there know why? I'm baffled, since it's pretty straightforward and totally brute force.

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  • Strange Bubble sort behaviour.

    - by user271528
    Can anyone explain why this bubble sort function doesn't work and why I loose number in my output. I'm very new to C, so please forgive me if this is something very obvious I have missed. #include <stdio.h> #include int bubble(int array[],int length) { int i, j; int temp; for(i = 0; i < (length); ++i) { for(j = 0; j < (length - 1); ++j) { if(array[i] array[i+1]) { temp = array[i+1]; array[i+1] = array[i]; array[i] = temp; } } } return 0; } int main() { int array[] = {12,234,3452,5643,0}; int i; int length; length = (sizeof(array)/sizeof(int)); printf("Size of array = %d\n", length); bubble(array, length); for (i = 0; i < (length); ++i) { printf("%d\n", array[i]); } return 0; } Output Size of array = 5 12 234 3452 0 0

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  • Need to add underscore to my regex

    - by TaMeR
    I suck at regular expression and just can't seem to figure this out. '/^[A-Za-z0-9](?:.[A-Za-z0-9]+)*$/' As it's right now it allows dots anytime after the first char and I like to add _ so that it allows both. Thanks

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  • How to get the original variable name of variable passed to a function

    - by Acorn
    Is it possible to get the original variable name of a variable passed to a function? E.g. foobar = "foo" def func(var): print var.origname So that: func(foobar) Returns: >>foobar EDIT: All I was trying to do was make a function like: def log(soup): f = open(varname+'.html', 'w') print >>f, soup.prettify() f.close() .. and have the function generate the filename from the name of the variable passed to it. I suppose if it's not possible I'll just have to pass the variable and the variable's name as a string each time.

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  • SQL Express Edition, SQL Compact Editin and SQLCMD for learning purpose

    - by Mil
    Hi, I want to learn programming in SQL from some SQL tutorial sites of which I heard of here but I need some environment for executing query's. I think I have both SQL CE and SQL EE installed on my computer but I have some doubts about these DBMS and I don't know exactly how to use SQLCMD utility so I hope someone here will have time and will to explain me the following: Since running sqlcmd -S.\sqlexpress at command prompt command gives "1" prompt I assume I have SQL express installed but anyway how can I be sure what I have installed on my machine since I cannot find in installed programs SQL Express Edition name? Can I ship and use database with my C# (VC# Express) application which was created with SQL EE (embedded?)? How can use sqlcmd for learning SQL, that is by issuing commands like create, use, select..., again emphasize is on learning SQL I do not want to run scripts but use interactive command prompt like with MySQL (since I want to use SQL I would pretty much like to avoid graphical tools for DBMS)? Please tell me if you have some other advice regarding as to what should I better use in learning how to program in SQL or should I stick with the above for now. Thanks in advance.

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  • Codeigniter: db data in controller

    - by Kevin Brown
    I'm confused about what to do... I'm working on a user's page where they can view certain things only if their supervisor has given them "money" or "credits". I need a simple way to get the person that is their supervisor by doing something like: $data['employer'] = $this->home_model->getEmployees(array('user_id'=>$manager_id)); Basically, get the user information about a person who's user_id matches the manager_id of the currently logged in member. I don't know how to set the variable $manager_id. Additional Information: The current user has an id, and a manager_id. I need the id of the manager. So, I need to grab the manager_id of the logged-in user and find the manager who's user_id is that of the manager_id. What's the process to do this? I can get each individually, but I don't know how to use one to get the other... I know it is confusing, but I'm confused! Thanks for the help!

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  • Inserting multiple types into an SQLite database with Python

    - by mankoff
    I'm trying to create an SQLite 3 database from Python. I have a few types I'd like to insert into each record: A float, and then 3 groups of n floats, currently a tuple but could be an array or list.. I'm not well-enough versed in Python to understand all the differences. My problem is the INSERT statement. DAS = 12345 lats = (42,43,44,45) lons = (10,11,12,13) times = (1,2,3,4,5,6,7,8,9) import sqlite3 connection = sqlite3.connect("test.db") cursor = connection.cursor() cursor.execute( "create table foo(DAS LONG PRIMARY KEY,lats real(4),lons real(4), times real(9) )" ) I'm not sure what comes next. Something along the lines of: cmd = 'INSERT into foo values (?,?,?,?), ..." cursor.execute(cmd) How should I best build the SQL insert command given this data?

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  • What is the single most influential book every programmer should read?

    - by NotMyself
    If you could go back in time and tell yourself to read a specific book at the beginning of your career as a developer, which book would it be? I expect this list to be varied and to cover a wide range of things. For me, the book would be Code Complete. After reading that book, I was able to get out of the immediate task mindset and begin to think about the bigger picture, quality and maintainability.

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  • How does PHP work - literature

    - by Ondrej Slinták
    I'm interested in literature (articles on internet, in magazines, books, podcasts - I don't really mind anything) that describes how PHP works internally, about its gotchas and perhaps some advanced functions. Is there anything like this out there? I tried to search on Google, but majority of articles were about starting with PHP and its basic functions. Any input is really welcome as I'm trying to understand the language internally - I'm tired of my mindless typing of code without understanding its essence.

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  • Am I doing getters/setters the right way in Java?

    - by Sergio Tapia
    public class Persona { int Codigo; String Nombre; public Persona(int Codigo, String Nombre){ this.Codigo = Codigo; this.Nombre = Nombre; } public void setCodigo(int Codigo){ this.Codigo = Codigo; } public int getCodigo(){ return this.Codigo; } public void setNombre(String Nombre){ this.Nombre = Nombre; } public String getNombre(){ return this.Nombre; } } Or is there a much shorter (realiable) way to do it?

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  • How should a programmer go about getting started with Flash/Flex/ActionScript?

    - by Graphics Noob
    What is the shortest path between zero (ie no flash related development software on my computer or information about where to obtain it or get started) to running a "hello world" ActionScript? I'm hoping for an answer that gives step by step instructions about exactly what software is needed to get started, an example of some "hello world" code, and instructions for compiling and running the code. I've spent more time than I think should be necessary researching this question and not found much information. Hopefully this question will be found by programmers like me who want to get started with Flash/Flex/ActionScript (After my morning of researching I still don't even know what terminology to use so I'll just throw it all out there). ActionScript tutorials I've found are focused on programming concepts, ie logic, branching, OOP, etc, and some even have code examples to download, but not a single one I've found explains how to compile and run the code. They all seem to assume you have an IDE standing by but no knowledge of programming, exactly the opposite of the position I'm in. Here are the most related SO questions I've found: http://stackoverflow.com/questions/59083/what-is-adobe-flex-is-it-just-flash-ii http://stackoverflow.com/questions/554899/getting-started-with-flex-3-ui-actionscript-programming http://stackoverflow.com/questions/2123105/how-to-learn-flex

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  • Problem running a Python program, error: Name 's' is not defined.

    - by Sergio Tapia
    Here's my code: #This is a game to guess a random number. import random guessTaken = 0 print("Hello! What's your name kid") myName = input() number = random.randint(1,20) print("Well, " + myName + ", I'm thinking of a number between 1 and 20.") while guessTaken < 6: print("Take a guess.") guess = input() guess = int(guess) guessTaken = guessTaken + 1 if guess < number: print("You guessed a little bit too low.") if guess > number: print("You guessed a little too high.") if guess == number: break if guess == number: guessTaken = str(guessTaken) print("Well done " + myName + "! You guessed the number in " + guessTaken + " guesses!") if guess != number: number = str(number) print("No dice kid. I was thinking of this number: " + number) This is the error I get: Name error: Name 's' is not defined. I think the problem may be that I have Python 3 installed, but the program is being interpreted by Python 2.6. I'm using Linux Mint if that can help you guys help me. Using Geany as the IDE and pressing F5 to test it. It may be loading 2.6 by default, but I don't really know. :( Edit: Error 1 is: File "GuessingGame.py", line 8, in <Module> myName = input() Error 2 is: File <string>, line 1, in <Module>

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  • How to retrieve Directories size including all sub-directories?

    - by vikingosegundo
    I have stored images from the net like this Documents/imagecache/domain1/original/path/inURI/foo.png Documents/imagecache/domain2/original/path/inURI/bar.png Documents/imagecache/... Documents/imagecache/... Now I'd like to check the size of imagecache including all it sub-directories. Is there a convenient way of doing it — preferable without crawling through all the data manually?

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  • Comparing a time delta in python

    - by Alpesh Patel
    I have a variable which is <type 'datetime.timedelta'> and I would like to compare it against certain values. Lets say d produces this datetime.timedelta value 0:00:01.782000 I would like to compare it like this: #if d is greater than 1 minute if d>1:00: print "elapsed time is greater than 1 minute" I have tried converting datetime.timedelta.strptime() but that does seem to work. Is there an easier way to compare this value?

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  • Python: re-initialize a function's default value for subsequent calls to the function.

    - by Peter Stewart
    I have a function that calls itself to increment and decrement a stack. I need to call it a number of times, and I'd like it to work the same way in subsequent calls but, as expected, it doesn't re-use the default value. I've read that this is a newbie trap and I've seen suggested solutions, but I haven't been able to make any solution work. It would be nice to be able to "fun.reset" def a(x, stack = [None]): print x,' ', stack if x > 5: temp = stack.pop() if x <=5: stack.append(1) if stack == []: return a(x + 1) print a(0) print a(2) #second call print a(3) #third call I expected this to work, but it doesn't. print a(0, [None]) print a(2, [None]) #second call print a(3, [None]) #third call Can I reset the function to it's initial state? Any help would be appreciated.

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  • perl hashes - comparing keys and values

    - by Aaron Moodie
    I've been reading over the perl doc, but I can't quite get my head around hashes. I'm trying to find if a hash key exists, and if so, compare is't value. The thing that is confusing me is that my searches say that you find if a key exists by if (exists $files{$key}) , but that $files{$key} also gives the value? the code i'm working on is: foreach my $item(@new_contents) { next if !-f "$directory/$item"; my $date_modified = (stat("$directory/$item"))[9]; if (exists $files{$item}) { if ($files{$item} != $date_modified { $files{$item} = $date_modified; print "$item has been modified\n"; } } else { $files{$item} = $date_modified; print "$item has been added\n"; } }

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  • What is a monad?

    - by kronoz
    Having briefly looked at Haskell recently I wondered whether anybody could give a brief, succinct, practical explanation as to what a monad essentially is? I have found most explanations I've come across to be fairly inaccessible and lacking in practical detail, so could somebody here help me?

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