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  • Unsigneds in order to prevent negative numbers

    - by Bruno Brant
    let's rope I can make this non-sujective Here's the thing: Sometimes, on fixed-typed languages, I restrict input on methods and functions to positive numbers by using the unsigned types, like unsigned int or unsigned double, etc. Most libraries, however, doesn't seem to think that way. Take C# string.Length. It's a integer, even though it can never be negative. Same goes for C/C++: sqrt input is an int or a double. I know there are reasons for this ... for example your argument might be read from a file and (no idea why) you may prefer to send the value directly to the function and check for errors latter (or use a try-catch block). So, I'm assuming that libraries are way better designed than my own code. So what are the reasons against using unsigned numbers to represent positive numbers? It's because of overflow when we cast then back to signed types?

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  • How to create a bash function with variable parameters/arguments to grep several keywords/tags

    - by CornSmith
    I'm using the :!grep "tag1" filename | grep "tag2" filename | grep -n "tag3 or more" filename command in vim to search for my code snippets based on their tags (a simple comment at the top of a snippet) in one big file. I use snippets to remember tricky things. This is painful to write out each time. I'd like to make an alias, or function to do something like this: :!greptag tag1 tag2 ... tag39 And it should search the current doc and return the lines with all the tags on them. Vim is set to interactive shell mode so that it can parse my bashrc for aliases/functions. set shellcmdflag=-ic How can I construct a function that allows for variable arguments like this in bash?

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  • Inheritance - initialization problem

    - by dumbquestion
    I have a c++ class derived from a base class in a framework. The derived class doesn't have any data members because I need it to be freely convertible into a base class and back - the framework is responsible for loading and saving the objects and I can't change it. My derived class just has functions for accessing the data. But there are a couple of places where I need to store some temporary local variables to speed up access to data in the base class. mydata* MyClass::getData() { if ( !m_mydata ) { // set to NULL in the constructor m_mydata = some_long_and complex_operation_to_get_the_data_in_the_base() } return m_mydata; } The problem is if I just access the object by casting the base class pointer returned from the framework to MyClass* the ctor for MyClass is never called and m_mydata is junk. Is there a way of only initializing the m_mydata pointer once?

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  • What to return as an iterator when there is no container?

    - by DaClown
    I have an inheritance structure of objects with begin() and end() as pure virtual member functions in the base class. From this objects I'm planning to build a composite structure. This inner objects have std::vector member the begin() and end() get their data from. But in a leaf class there is no vector. Now I try to find a return value for begin() and end() in the leaf classes. What would be a good way to do that? The easiest way would be to have a vector member in the leaf classes with no elements in it to fuel begin() and end(), but this just doesn't feel right.

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  • Java escape HTML - string replace slow?

    - by cpf
    Hi StackOverflow, I have a Java application that makes heavy use of a large file, to read, process and give through to SolrEmbeddedServer (http://lucene.apache.org/solr/). One of the functions does basic HTML escaping: private String htmlEscape(String input) { return input.replace("&", "&amp;").replace(">", "&gt;").replace("<", "&lt;") .replace("'", "&apos;").replaceAll("\"", "&quot;"); } While profiling the application, the program spends roughly 58% of the time in this function, a total of 47% in replace, and 11% in replaceAll. Now, is the Java replace that slow, or am I on the right path and should I consider the program efficient enough to have its bottleneck in Java and not in my code? (Or am I replacing wrong?) Thanks in advance!

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  • Python: How To copy function parameters into object's fields effortlessly ?

    - by bandana
    Many times I have member functions that copy parameters into object's fields. For Example: class NouveauRiches(object): def __init__(self, car, mansion, jet, bling): self.car = car self.mansion = mansion self.jet = jet self.bling = bling Is there a python language construct that would make the above code less tedious? One could use *args: def __init__(self, *args): self.car, self.mansion, self.jet, self.bling = args +: less tedious -: function signature not revealing enough. need to dive into function code to know how to use function -: does not raise a TypeError on call with wrong # of parameters (but does raise a ValueError) Any other ideas? (Whatever your suggestion, make sure the code calling the function does stays simple)

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  • R: how to make a unique set of names from a vector of strings?

    - by Mike Dewar
    Hi, I have a vector of strings. Check out my vector, it's awesome: > awesome [1] "a" "b" "c" "d" "d" "e" "f" "f" I'd like to make a new vector that is the same length as awesome but where, if necessary, the strings have been uniqueified. For example, a valid output of my desired function would be > awesome.uniqueified [1] "a" "b" "c" "d.1" "d.2" "e" "f.1" "f.2" Is there an easy, R-thonic and beautiful way to do this? I should say my list in real life (it's not called awesome) contains 25000ish mircoarray probeset identifiers. I'm always nervous when I embark on writing little generic functions (which I'm sure I could do) as I'm sure some R guru has come across this problem in the past, nailed it with some incredible algorithm that doesn't even have to store more than half an element in the vector. I'm just not sure what they might have called it. Probably not uniqueify.

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  • Linux - Programmatically write to a proc file

    - by Zach
    I have found several examples online where we can create a proc file, assign read and write methods that are called every time the proc file is opened for read or written to. However, I can't seem to find any documentation on how to programatically write to a proc file. Ideally, I would like to add a timestamp with other user details every time the proc file is opened for read or for write. Again, I've found where I can add the read and write functions that are triggered when the proc file is opened, but I can't find documentation on how to actually write to a proc file programatically. This would be different from a regular IO read/write, correct?

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  • checksum error with building an HTTP packet(but over TCP, like syn/ack its ok)

    - by Hila
    I am building a NAT program,I change each packet that comes from our internal subnet, change it's source IP address by libnet functions.( catch the packet with libpcap, put it sniff structures and build the new packet with libnet) I am trying to build an http packet. When I look on wireshark, I see that the new packet that I have built is exectly like the original packet(the only diffrent is that I changed the src port and ip), but there is a checksum error, So the server don't do anything with the packet that I have sent to him, beacuse the cheksum field is wrong. When I send a tcp packet(like syn or ack), the checksum is ok, and the server respons. Is anyone knows what can cause this problem? the new checksum in other packets is calculated as it should be.. but in the HTTP packet it doesn't..

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  • What is the Perl equivalent to C's #include? [closed]

    - by Herms
    Possible Duplicate: How do I include functions from another file in my Perl script? I have a couple simple perl scripts that share some subroutines. I'd like to pull those subroutines out into another file, but I'm not sure how to go about doing that. All I need is an equivalent to C's #include. I found a couple things online about creating modules, but that seems like overkill for what I'm doing. Is there a way to just tell perl to load/execute another perl script inline, so it's treated as if it's just part of the file (like #include in C)?

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  • Design pattern: polymorphisim for list of objects

    - by ziang
    Suppose I have a class A, and A1, A2 inherits from A. There are 2 functions: List<A1> getListA1(){...} List<A2> getListA2(){...} Now I want to do something similar to both A1 and A2 in another function public void process(List<A>){...} If I want to pass the instance of either ListA1 or ListA2, of course the types doesn't match because the compiler doesn't allow the coercion from List< A1 to List< A. I can't do something like this: List<A1> listA1 = getListA1(); List<A> newList = (List<A>)listA1; //this is not allowed. So what is the best approach to the process()? Is there any way to do it in a universal way rather than write the similar code to both List and List?

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  • Defining multiple VBA objects within one function or sub-routine?

    - by Harokitty
    I have the following VBA code: Option Explicit Private a(2) as Double Private b(2) as Double Public Function Hello(X1 As Double, X2 As Double) As Double a(1) = X1 + X2 a(2) = X1/X2 b(1) = X1 b(2) = X2^2 Hello = a(1)+a(2)+b(1)+b(2) End Function Within the function Hello I have defined a(1),a(2),b(1),b(2). However, I want to make some function or sub-routine that accepts X1 and X2 as arguments and spits out the values for a(1),a(2),b(1),b(2). This is because I use the above definitions for a(1),a(2),b(1),b(2) in about 20 functions in my module and would like to avoid having to do the following in each function that I use thesis in: a(1) = X1 + X2 a(2) = X1/X2 b(1) = X1 b(2) = X2^2

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  • Python Etiquette: Importing Modules

    - by F3AR3DLEGEND
    Say I have two Python modules: module1.py: import module2 def myFunct(): print "called from module1" module2.py: def myFunct(): print "called from module2" def someFunct(): print "also called from module2" If I import module1, is it better etiquette to re-import module2, or just refer to it as module1.module2? For example (someotherfile.py): import module1 module1.myFunct() # prints "called from module1" module1.module2.myFunct() # prints "called from module2" I can also do this: module2 = module1.module2. Now, I can directly call module2.myFunct(). However, I can change module1.py to: from module2 import * def myFunct(): print "called from module1" Now, in someotherfile.py, I can do this: import module1 module1.myFunct() # prints "called from module1"; overrides module2 module1.someFunct() # prints "also called from module2" Also, by importing *, help('module1') shows all of the functions from module2. On the other hand, (assuming module1.py uses import module2), I can do: someotherfile.py: import module1, module2 module1.myFunct() # prints "called from module1" module2.myFunct() # prints "called from module2" Again, which is better etiquette and practice? To import module2 again, or to just refer to module1's importation?

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  • How to maipulate the shell output in php

    - by Mirage
    I am trying to write php script which does some shell functions like reporting. So i am starting with diskusage report I want in following format drive path ------------total-size --------free-space Nothing else My script is $output = shell_exec('df -h -T'); echo "<pre>$output</pre>"; and its ouput is like below Filesystem Type Size Used Avail Use% Mounted on /dev/sda6 ext3 92G 6.6G 81G 8% / none devtmpfs 3.9G 216K 3.9G 1% /dev none tmpfs 4.0G 176K 4.0G 1% /dev/shm none tmpfs 4.0G 1.1M 4.0G 1% /var/run none tmpfs 4.0G 0 4.0G 0% /var/lock none tmpfs 4.0G 0 4.0G 0% /lib/init/rw /dev/sdb1 ext3 459G 232G 204G 54% /media/Server /dev/sdb2 fuseblk 466G 254G 212G 55% /media/BACKUPS /dev/sda5 fuseblk 738G 243G 495G 33% /media/virtual_machines How can i convert that ouput into my forn\matted output

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  • Php code not executing - dies out when trying to refer to member of static class - no error displaye

    - by Ali
    I'm having some problems with this piece of code. I've included a class declaration and trying to create an object of that class but my code dies out. It doesn't seem to be an include issue as all the files are being included even the files called for inclusion within the class file itself. However the object is not created - I tried to put an echo statement in the __construct function but nothing it just doesn't run infact doesn't create the object and the code won't continue from there - plus no error is reported or displayed and I have error reporting set to E_ALL and display errors set to true WHats happening here :( =============EDIT SOrry I checked again the error is prior to teh object creation thing - it dies out when it tries to refer to a constant in a static class like so: $v = Zend_Oauth::REQUEST_SCHEME_HEADER; THis is the class or part of it - it has largely static functions its the Zend Oauth class: class Zend_Oauth { const REQUEST_SCHEME_HEADER = 'header'; const REQUEST_SCHEME_POSTBODY = 'postbody'; const REQUEST_SCHEME_QUERYSTRING = 'querystring'; // continued LIke I said no error is being reported at all :(

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  • biginteger calculation problem

    - by murali
    I am using the following code but the parameters are not passed to the methods. BigInteger p = BigInteger.valueOf(0); BigInteger u1 = obj.bigi_calc(g1, l); In this g1,l are long values. The method is private BigInteger bigi_calc(long g1, long l){ BigInteger cal = BigInteger.valueOf(g1); BigInteger cal1= BigInteger.valueOf(l); for(BigInteger f = BigInteger.ONE;f.compareTo(cal1)>0;f=f.add(BigInteger.ONE)){ //BigInteger p= BigInteger.valueOf(0); p = cal.multiply(cal1); System.out.println("check p"+p); } // System.out.println("check p"+p); return p; } The elipse shows that it may be out of sync, but the parameters are not passed to the functions. Can you please help me to solve this problem?

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  • Should I use DATE and TIME as fields rather than DATETIME

    - by whitstone86
    I have a project on going for a TV guide, called mytvguide in the database - I use PHPMyAdmin. This is the structure for one table, which is called tvshow1: Field Type channel varchar(255) date date No airdate time No expiration time No episode varchar(255) setreminder varchar(255) but am not sure how to get DATE, TIME to work with the pagination script (below is the script, which works for the version with DATETIME): http://pastebin.com/6S1ejAFJ However, although the DATETIME one works - it shows programmes that air on the day itself like this: Programme 1 showing on Channel 1 2:35pm "Episode 2" Set Reminder Programme 1 showing on Channel 1 May 26th - 12:50pm "Episode 3" Set Reminder Programme 1 showing on Channel 1 May 26th - 5:55pm "Episode 3" Set Reminder but I'm not quite sure how to replicate that for the fields that use DATE, TIME functions as seen above. Any advice on this is appreciated, thanks!

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  • Are there any context-sensitive code search tools?

    - by Vicky
    I have been getting very frustrated recently in dealing with a massive bulk of legacy code which I am trying to get familiar with. Say I try to search for a particular function call, I get loads of results that turn out to be completely irrelevant; some of them are easy to spot, eg a comment saying // Fixed functionality in foo() so don't need to handle this here any more But others are much harder to spot manually, because they turn out to be calls from other functions in modules that are only compiled in certain cases, or are part of a much larger block of code that is #if 0'd out in its entirety. What I'd like would be a search tool that would allow me to search for a term and give me the choice to include or exclude commented out or #if 0'd out code. Then the search results would be displayed alongside a list of #defines that are required in order for that snippet of code to be relevant. I'm working in C / C++, but other than the specific comment syntax I guess the techniques should be more generally applicable. Does such a tool exist?

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  • JavaScript using toString on a Function object to read text content

    - by mseeley
    Calling toString() on the function below returns different strings across browsers. I understand this is because ECMA-262 15.3.4.2 leaves wiggle room for each vendor. Chrome returns the comments in addition to all syntax. Sadly Firefox 3.6 omits the comments. Based on Firefox's behavior I haven't tested IE, Opera, or Safari. function foo() { /* comment */ var bar = true; } Specifically, I am attempting to embed meta data within a specially formatted comment block within a function. Later the return value of the functions toString() method would be parsed and values returned as an object. I've been unable to locate compatibility tables or alternatives to toString(). Does the community have any ideas? Btw, pre-processing JS files isn't an option. :( Thanks a lot. :)

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  • How to make schema and code dynamic?

    - by Jonarch
    I want to make my database schema and application code as dynamic as possible to handle "unknown" use cases and changes. Developing in PHP and MySQL. Twice now I have had to change my entire schema including table and column names and this means the developers have to go back to the application code and modify all the SQL queries and table/columns names. So to prevent this I want to if just like we do on pages where we have page content, title bar etc dynamic like a %variable%, can we do it for the schema and maybe even for the php code functions and classes somehow? It takes weeks to re-do all changes like this vs if it is dynamic it can be done in under a day.

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  • What's the best way to call jQuery scripts, in HTML/PHP template, or seperate js file?

    - by j-man86
    StackOverflow is telling me this is a subjective question, but I think it's a matter of fact! I have a number of scripts that I'm using on different parts of my site. In terms of making fewer http requests, I know it's better to combine all of these scripts into one .js file. However, isn't a waste of time for a page to call a .js full of 10 or 15 different functions when it's only using one? The other method I am using is to use PHP conditional statements... <?php if( is_page() ) { > $(document).ready(function(){ ... }); <?php } ?> What's the best method or comination of these methods?

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  • folder structure for project documentation

    - by Qiulang
    Hi all, I saw some questions raised about the folder structure of source codes, but I never see the question about folder structure of project documentation. I googled it and still do not see many articles talk about. Here is one http://www.projectperfect.com.au/downloads/Info/info_project_folder_structure.pdf To quote some of its words: "There are two broad approaches: Organize by phase so that each top directory is a phase. For example, you might have directories for Feasibility, Business Analysis, Design etc. or whatever your phases are called. Organize by function so that the top directory level are functions. For example, Risks, Requirements, Scope, Change Control, Development. Most times a mix of both are used..." So any thought about it? I believe this is also an important issue!

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  • Ways to optimize Android App code based on function call stack?

    - by K-RAN
    I've been told that Android OS stores all function calls in a stack. This can lead to many problems and cause the 'hiccups' during runtime, even if a program is functionalized properly, correct? So the question is, how can we prevent this from happening? The obvious solution is to functionalize less, along with other sensible acts such as refraining from excessively/needlessly creating objects, performing static calls to functions that don't access fields, etc... Is there another way though? Or can this only be done through careful code writing on the programmers' part? Does the JVM/JIT automatically optimize the bytecode during compile time to account for this?? Thanks a lot for your responses!!

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  • Selenium selected option in dropdown not displayed correctly

    - by luckyfool
    I have the following issue with Selenium Webdriver. There are two dropdown menus on a page i am testing "brand" and "items". The options of "items" depend on which brand you choose. I am trying to iterate through all possible choices and print brand-item pairs. I use two possible ways to pick an option from each dropdown menu Using Select(): def retryingSelectOption(name,n): result=False attempts=0 while attempts<5: try: element=Select(driver.find_element_by_name(name)) element.select_by_index(n) print element.all_selected_options[0].text result=True break except StaleElementReferenceException: pass attempts+=1 return result And using .click(): def retryingClickOption(name,n): result=False attempts=0 while attempts<5: try: driver.find_element_by_name(name).find_elements_by_tag_name("option")[n].click() result=True break except StaleElementReferenceException: pass attempts+=1 return result My problem is that at ,what seem to me as random moments (sometimes it works sometimes it does not), even though the above functions return True and printing out the selected option shows me the correct answer, the browser still displays the previous option. So basically Selenium tells me i have picked the right option but the browser displays the previous one.No idea what is wrong.

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  • Space requirements of a merge-sort

    - by Arkaitz Jimenez
    I'm trying to understand the space requirements for a Mergesort, O(n). I see that time requirements are basically, amount of levels(logn) * merge(n) so that makes (n log n). Now, we are still allocating n per level, in 2 different arrays, left and right. I do understand that the key here is that when the recursive functions return the space gets deallocated, but I'm not seeing it too obvious. Besides, all the info I find, just states space required is O(n) but don't explain it. Any hint? function merge_sort(m) if length(m) = 1 return m var list left, right, result var integer middle = length(m) / 2 for each x in m up to middle add x to left for each x in m after middle add x to right left = merge_sort(left) right = merge_sort(right) result = merge(left, right) return result

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