Search Results

Search found 6580 results on 264 pages for 'boost foreach'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 25/264 | < Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >

  • C++ boost mpl vector

    - by Gokul
    I understand that the following code won't work, as i is a runtime parameter and not a compile time parameter. But i want to know, whether there is a way to achieve the same. i have a list of classes and i need to call a template function, with each of these classes. void GucTable::refreshSessionParams() { typedef boost::mpl::vector< SessionXactDetails, SessionSchemaInfo > SessionParams; for( int i = 0; i < boost::mpl::size<SessionParams>::value; ++i ) boost::mpl::at<SessionParams, i>::type* sparam = g_getSessionParam< boost::mpl::at<SessionParams, i>::type >(); sparam->updateFromGucTable(this); } } Can someone suggest me a easy and elegant way to perform the same? i need to iterate through the mpl::vector and use the type to call a global function and then use that parameter to do some run-time operations. Thanks in advance, Gokul. Working code typedef boost::mpl::vector< SessionXactDetails, SessionSchemaInfo > SessionParams; class GucSessionIterator { private: GucTable& m_table; public: GucSessionIterator(GucTable& table) :m_table(table) { } template< typename U > void operator()(const U& ) { g_getSessionParam<U>()->updateFromGucTable(m_table); } }; void GucTable::refreshSessionParams() { boost::mpl::for_each< SessionParams >( GucSessionIterator(*this) ); return; }

    Read the article

  • g++: Use ZIP files as input

    - by Notinlist
    We have the Boost library in our side. It consists of huge amount of files which are not changing ever and only a tiny portion of it is used. We swap the whole boost directory if we are changing versions. Currently we have the Boost sources in our SVN, file by file which makes the checkout operations very slow, especially on Windows. It would be nice if there were a notation / plugin to address C++ files inside ZIP files, something like: // @ZIPFS ASSIGN 'boost' 'boost.zip/boost' #include <boost/smart_ptr/shared_ptr.hpp> Are there any support for compiler hooks in g++? Are there any effort regarding ZIP support? Other ideas?

    Read the article

  • Does the for foreach construct in java create a hard or soft copy?

    - by Doug
    Say I have the following piece of java code ArrayList<Double> myList = new Double[100]; for (Double x : myList) x = randomDouble(); Does this actually modify myList or just the dummy variable? I realize I should just try this code segment out, but I think this is the sort of thing I should be able to google or search for on this site, and several queries so far have turned up nothing useful.

    Read the article

  • How to simply a foreach iteration using reflection

    - by Priya
    Consider that I have to get the overall performance of X. X has Y elements and Y in turn has Z elements which inturn has some N elements. To get the performance of X I do this: List<double> XQ = new List<double>(); foreach (Elem Y in X.Y){ List<double> YQ = new List<double>(); foreach (Elem Z in Y.Z){ List<double> ZQ = new List<double>(); foreach (Elem N in Z.N){ ZQ.Add(GetPerformance(N)); } YQ.Add(AVG(ZQ)); } XQ.Add(AVG(YQ)); } AVG of XQ list gives the performance of X. The performance can be calculated for either X or Y or for Z. X, Y and Z share the same base class. So depending on the item given the foreach loop has to be executed. Currently I have a switch case to determine each item (X or Y or Z) and the foreach loop is repeated in the code pertaining to the item (eg. If Y foreach starts from Y.Z). Is is possible to convert this whole code generic using reflection instead of having to repeat it in each switch case? Thanks

    Read the article

  • VC9 C1083 Cannot open include file: 'boost...' after trying to abstract an include dependency

    - by ronivek
    Hey, So I've been working on a project for the past number of weeks and it uses a number of Boost libraries. In particular I'm using the boost::dynamic_bitset library quite extensively. I've had zero issues up until now; but tonight I discovered a dependency between some includes which I had to resolve; and I tried to do so by providing an abstract callback class. Effectively I now have the following: First include... class OtherClassCallback { public: virtual int someOtherMethod() const = 0; }; class SomeClass { public: void someMethod(OtherClassCallback *oc) { ... oc->someOtherMethod(); ... } }; Second include... #include "SomeClass.h" class SomeOtherClass : public OtherClassCallback { public: int someOtherMethod() const { return this->someInt; } }; Here is the issue; ever since I implemented this class I'm now getting the following error: fatal error C1083: Cannot open include file: 'boost/dynamic_bitset/dynamic_bitset.hpp': No such file or directory Now I'm getting no other compiler errors; and it's a pretty substantial project. My include paths and so on are perfect; my files are fully accessible and removing the changes fixes the issue. Does anyone have any idea what might be going on? I'm compiling to native Windows executables in VS9. I should confess that I'm very inexperienced with C++ in general so go easy on me if it's something horribly straightforward; I can't figure it out.

    Read the article

  • Can't add/remove items from a collection while foreach is iterating over it

    - by flockofcode
    If I make my own implementation of IEnumerator interface, then I am able ( inside foreach statement )to add or remove items from a albumsList without generating an exception.But if foreach statement uses IEnumerator supplied by albumsList, then trying to add/delete ( inside the foreach )items from albumsList will result in exception: class Program { static void Main(string[] args) { string[] rockAlbums = { "rock", "roll", "rain dogs" }; ArrayList albumsList = new ArrayList(rockAlbums); AlbumsCollection ac = new AlbumsCollection(albumsList); foreach (string item in ac) { Console.WriteLine(item); albumsList.Remove(item); //works } foreach (string item in albumsList) { albumsList.Remove(item); //exception } } class MyEnumerator : IEnumerator { ArrayList table; int _current = -1; public Object Current { get { return table[_current]; } } public bool MoveNext() { if (_current + 1 < table.Count) { _current++; return true; } else return false; } public void Reset() { _current = -1; } public MyEnumerator(ArrayList albums) { this.table = albums; } } class AlbumsCollection : IEnumerable { public ArrayList albums; public IEnumerator GetEnumerator() { return new MyEnumerator(this.albums); } public AlbumsCollection(ArrayList albums) { this.albums = albums; } } } a) I assume code that throws exception ( when using IEnumerator implementation A supplied by albumsList ) is located inside A? b) If I want to be able to add/remove items from a collection ( while foreach is iterating over it), will I always need to provide my own implementation of IEnumerator interface, or can albumsList be set to allow adding/removing items? thank you

    Read the article

  • ForEach loop in Mathematica.

    - by dreeves
    I'd like something like this: ForEach[i_, {1,2,3}, Print[i] ] Or, more generally, to destructure arbitrary stuff in the list you're looping over, like: ForEach[{i_, j_}, {{1,10}, {2,20}, {3,30}}, Print[i*j] ] (Meta-question: is that a good way to call a ForEach loop, with the first argument a pattern like that?) ADDED: Some answerers have rightly pointed out that usually you want to use Map or other purely functional constructs and eschew a non-functional programming style where you use side effects. I agree! But here's an example where I think this ForEach construct is supremely useful: Say I have a list of options (rules) that pair symbols with expressions, like attrVals = {a -> 7, b -> 8, c -> 9} Now I want to make a hash table where I do the obvious mapping of those symbols to those numbers. I don't think there's a cleaner way to do that than ForEach[a_ -> v_, attrVals, h[a] = v] ADDED: I just realized that to do ForEach properly, it should support Break[] and Continue[]. I'm not sure how to implement that. Perhaps it will need to somehow be implemented in terms of For, While, or Do since those are the only loop constructs that support Break[] and Continue[]. If anyone interested in this wants to ask about that as a separate question, please do!

    Read the article

  • When does an asio timer go out of scope?

    - by ApplePieIsGood
    What I mean is, let's say you do an async_wait on an asio timer and bind the update to a function that takes a reference to a type T. Let's say you created the T initially on the stack before passing it to async_wait. At the end of that async_wait, it calls async_wait itself, renewing the timer over and over. Does that stack allocated type T stay alive until the first time the timer doesn't renew itself, or after the first invocation of the function will the T go out of scope?

    Read the article

  • Cumulative +1/-1 Cointoss crashes on 1000 iterations. Please advise; c++ boost random libraries

    - by user1731972
    following some former advice Multithreaded application, am I doing it right? I think I have a threadsafe number generator using boost, but my program crashes when I input 1000 iterations. The output .csv file when graphed looks right, but I'm not sure why it's crashing. It's using _beginthread, and everyone is telling me I should use the more (convoluted) _beingthreadex, which I'm not familiar with. If someone could recommend an example, I would greatly appreciate it. Also... someone pointed out I should be applying a second parameter to my _beginthread for the array counting start positions, but I have no idea how to pass more than one parameter, other than attempting to use a structure, and I've read structure's and _beginthread don't get along (although, I could just use the boost threads...) #include <process.h> #include <windows.h> #include <iostream> #include <fstream> #include <time.h> #include <random> #include <boost/random.hpp> //for srand48_r(time(NULL), &randBuffer); which doesn't work #include <stdio.h> #include <stdlib.h> //#include <thread> using namespace std; using namespace boost; using namespace boost::random; void myThread0 (void *dummy ); void myThread1 (void *dummy ); void myThread2 (void *dummy ); void myThread3 (void *dummy ); //for random seeds void initialize(); //from http://stackoverflow.com/questions/7114043/random-number-generation-in-c11-how-to-generate-how-do-they-work uniform_int_distribution<> two(1,2); typedef std::mt19937 MyRNG; // the Mersenne Twister with a popular choice of parameters uint32_t seed_val; // populate somehow MyRNG rng1; // e.g. keep one global instance (per thread) MyRNG rng2; // e.g. keep one global instance (per thread) MyRNG rng3; // e.g. keep one global instance (per thread) MyRNG rng4; // e.g. keep one global instance (per thread) //only needed for shared variables //CRITICAL_SECTION cs1,cs2,cs3,cs4; // global int main() { ofstream myfile; myfile.open ("coinToss.csv"); int rNum; long numRuns; long count = 0; int divisor = 1; float fHolder = 0; long counter = 0; float percent = 0.0; //? //unsigned threadID; //HANDLE hThread; initialize(); HANDLE hThread[4]; const int size = 100000; int array[size]; printf ("Runs (uses multiple of 100,000) "); cin >> numRuns; for (int a = 0; a < numRuns; a++) { hThread[0] = (HANDLE)_beginthread( myThread0, 0, (void*)(array) ); hThread[1] = (HANDLE)_beginthread( myThread1, 0, (void*)(array) ); hThread[2] = (HANDLE)_beginthread( myThread2, 0, (void*)(array) ); hThread[3] = (HANDLE)_beginthread( myThread3, 0, (void*)(array) ); //waits for threads to finish before continuing WaitForMultipleObjects(4, hThread, TRUE, INFINITE); //closes handles I guess? CloseHandle( hThread[0] ); CloseHandle( hThread[1] ); CloseHandle( hThread[2] ); CloseHandle( hThread[3] ); //dump array into calculations //average array into fHolder //this could be split into threads as well for (int p = 0; p < size; p++) { counter += array[p] == 2 ? 1 : -1; //cout << array[p] << endl; //cout << counter << endl; } //this fHolder calculation didn't work //fHolder = counter / size; //so I had to use this cout << counter << endl; fHolder = counter; fHolder = fHolder / size; myfile << fHolder << endl; } } void initialize() { //seed value needs to be supplied //rng1.seed(seed_val*1); rng1.seed((unsigned int)time(NULL)); rng2.seed(((unsigned int)time(NULL))*2); rng3.seed(((unsigned int)time(NULL))*3); rng4.seed(((unsigned int)time(NULL))*4); }; void myThread0 (void *param) { //EnterCriticalSection(&cs1); //aquire the critical section object int *i = (int *)param; for (int x = 0; x < 25000; x++) { //doesn't work, part of merssene twister //i[x] = next(); i[x] = two(rng1); //original srand //i[x] = rand() % 2 + 1; //doesn't work for some reason. //uint_dist2(rng); //i[x] = qrand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs1); // release the critical section object } void myThread1 (void *param) { //EnterCriticalSection(&cs2); //aquire the critical section object int *i = (int *)param; for (int x = 25000; x < 50000; x++) { //param[x] = rand() % 2 + 1; i[x] = two(rng2); //i[x] = rand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs2); // release the critical section object } void myThread2 (void *param) { //EnterCriticalSection(&cs3); //aquire the critical section object int *i = (int *)param; for (int x = 50000; x < 75000; x++) { i[x] = two(rng3); //i[x] = rand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs3); // release the critical section object } void myThread3 (void *param) { //EnterCriticalSection(&cs4); //aquire the critical section object int *i = (int *)param; for (int x = 75000; x < 100000; x++) { i[x] = two(rng4); //i[x] = rand() % 2 + 1; //cout << i[x] << endl; } //LeaveCriticalSection(&cs4); // release the critical section object }

    Read the article

  • functional, bind1st and mem_fun

    - by Neil G
    Why won't this compile? #include <functional> #include <boost/function.hpp> class A { A() { typedef boost::function<void ()> FunctionCall; FunctionCall f = std::bind1st(std::mem_fun(&A::process), this); } void process() {} }; Errors: In file included from /opt/local/include/gcc44/c++/bits/stl_function.h:712, from /opt/local/include/gcc44/c++/functional:50, from a.cc:1: /opt/local/include/gcc44/c++/backward/binders.h: In instantiation of 'std::binder1st<std::mem_fun_t<void, A> >': a.cc:7: instantiated from here /opt/local/include/gcc44/c++/backward/binders.h:100: error: no type named 'second_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:103: error: no type named 'first_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:106: error: no type named 'first_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:111: error: no type named 'second_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h:117: error: no type named 'second_argument_type' in 'class std::mem_fun_t<void, A>' /opt/local/include/gcc44/c++/backward/binders.h: In function 'std::binder1st<_Operation> std::bind1st(const _Operation&, const _Tp&) [with _Operation = std::mem_fun_t<void, A>, _Tp = A*]': a.cc:7: instantiated from here /opt/local/include/gcc44/c++/backward/binders.h:126: error: no type named 'first_argument_type' in 'class std::mem_fun_t<void, A>' In file included from /opt/local/include/boost/function/detail/maybe_include.hpp:13, from /opt/local/include/boost/function/detail/function_iterate.hpp:14, from /opt/local/include/boost/preprocessor/iteration/detail/iter/forward1.hpp:47, from /opt/local/include/boost/function.hpp:64, from a.cc:2: /opt/local/include/boost/function/function_template.hpp: In static member function 'static void boost::detail::function::void_function_obj_invoker0<FunctionObj, R>::invoke(boost::detail::function::function_buffer&) [with FunctionObj = std::binder1st<std::mem_fun_t<void, A> >, R = void]': /opt/local/include/boost/function/function_template.hpp:913: instantiated from 'void boost::function0<R>::assign_to(Functor) [with Functor = std::binder1st<std::mem_fun_t<void, A> >, R = void]' /opt/local/include/boost/function/function_template.hpp:722: instantiated from 'boost::function0<R>::function0(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = std::binder1st<std::mem_fun_t<void, A> >, R = void]' /opt/local/include/boost/function/function_template.hpp:1064: instantiated from 'boost::function<R()>::function(Functor, typename boost::enable_if_c<boost::type_traits::ice_not::value, int>::type) [with Functor = std::binder1st<std::mem_fun_t<void, A> >, R = void]' a.cc:7: instantiated from here /opt/local/include/boost/function/function_template.hpp:153: error: no match for call to '(std::binder1st<std::mem_fun_t<void, A> >) ()'

    Read the article

  • How can I boost the volume of my Video

    - by Sunny Shah.
    I have a video that I need to pass on to some of my friends but it has very low audio volume. How can I boost the audio volume in this video so that it has a similar level as my other videos? Is there a video converter that can boost the audio volume?

    Read the article

  • Anyone have an XSL to convert Boost.Test XML logs to a presentable format?

    - by Stuart Lange
    I have some C++ projects running through cruisecontrol.net. As a part of the build process, we compile and run Boost.Test unit test suites. I have these configured to dump XML log files. While the format is similar to JUnit/NUnit, it's not quite the same (and lacks some information), so cruisecontrol.net is unable to pick them up. I am wondering if anyone has created (or knows of) an existing XSL transform that will convert Boost.Test results to JUnit/NUnit format, or alternatively, directly to a presentable (html) format. Thanks!

    Read the article

  • How can I convert Perl regular expressions to boost regular expressions?

    - by YY
    I'm not familiar with Perl and boost regular expression and I want to convert a Perl code to c++. I want to convert special regular expression in Perl into c++ using Boost regexp library. Please help me understand what I must do? Here is some regexps that a word of a sentence may match: if ($word =~ /^[\.:\,()\'\`-]/) { # hack for punctuation } if ($word =~ /^[A-Z]/) { return; } if ($word =~ /[A-Za-z0-9]+\-[A-Za-z0-9]+/) { # all hyphenated words return; } if ($word =~ /.*[0-9].*/) { # all numbers return; }

    Read the article

  • C++ Boost ASIO: how to read/write with a timeout?

    - by Stéphane
    From reading other Stackoverflow entries and the boost::asio documentation, I've confirmed that there is no synchronous asio read/write calls that also provide an easy-to-use timeout as a parameter to the call. I'm in the middle of converting an old-school linux socket app with select(2) calls that employs timeouts, and I need to do more-or-less the same. So what is the best way to do this in boost::asio? Looking at the asio documentation, there are many confusing examples of various things to do with timers, but I'm quite confused. I'd love to see a simple-to-read example of this: Read from a socket, but wait for a maximum of X seconds after which the function either returns with nothing, or returns with whatever it was able to read from the socket before the timeout expired.

    Read the article

  • Use Extension method to write cleaner code

    - by Fredrik N
    This blog post will show you step by step to refactoring some code to be more readable (at least what I think). Patrik Löwnedahl gave me some of the ideas when we where talking about making code much cleaner. The following is an simple application that will have a list of movies (Normal and Transfer). The task of the application is to calculate the total sum of each movie and also display the price of each movie. class Program { enum MovieType { Normal, Transfer } static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies) { if (movie == MovieType.Normal) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } else if (movie == MovieType.Transfer) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } } } private static IEnumerable<MovieType> GetMovies() { return new List<MovieType>() { MovieType.Normal, MovieType.Transfer, MovieType.Normal }; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } In the code above I’m using an enum, a good way to add types (isn’t it ;)). I also use one foreach loop to calculate the price, the loop has a condition statement to check what kind of movie is added to the list of movies. I want to reuse the foreach only to increase performance and let it do two things (isn’t that smart of me?! ;)). First of all I can admit, I’m not a big fan of enum. Enum often results in ugly condition statements and can be hard to maintain (if a new type is added we need to check all the code in our app to see if we use the enum somewhere else). I don’t often care about pre-optimizations when it comes to write code (of course I have performance in mind). I rather prefer to use two foreach to let them do one things instead of two. So based on what I don’t like and Martin Fowler’s Refactoring catalog, I’m going to refactoring this code to what I will call a more elegant and cleaner code. First of all I’m going to use Split Loop to make sure the foreach will do one thing not two, it will results in two foreach (Don’t care about performance here, if the results will results in bad performance, you can refactoring later, but computers are so fast to day, so iterating through a list is not often so time consuming.) Note: The foreach actually do four things, will come to is later. var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies) { if (movie == MovieType.Normal) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } } foreach (var movie in movies) { if (movie == MovieType.Transfer) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To remove the condition statement we can use the Where extension method added to the IEnumerable<T> and is located in the System.Linq namespace: foreach (var movie in movies.Where( m => m == MovieType.Normal)) { totalPriceOfNormalMovie += 2; Console.WriteLine("$2"); } foreach (var movie in movies.Where( m => m == MovieType.Transfer)) { totalPriceOfTransferMovie += 3; Console.WriteLine("$3"); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The above code will still do two things, calculate the total price, and display the price of the movie. I will not take care of it at the moment, instead I will focus on the enum and try to remove them. One way to remove enum is by using the Replace Conditional with Polymorphism. So I will create two classes, one base class called Movie, and one called MovieTransfer. The Movie class will have a property called Price, the Movie will now hold the price:   public class Movie { public virtual int Price { get { return 2; } } } public class MovieTransfer : Movie { public override int Price { get { return 3; } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The following code has no enum and will use the new Movie classes instead: class Program { static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = 0; int totalPriceOfTransferMovie = 0; foreach (var movie in movies.Where( m => m is Movie)) { totalPriceOfNormalMovie += movie.Price; Console.WriteLine(movie.Price); } foreach (var movie in movies.Where( m => m is MovieTransfer)) { totalPriceOfTransferMovie += movie.Price; Console.WriteLine(movie.Price); } } private static IEnumerable<Movie> GetMovies() { return new List<Movie>() { new Movie(), new MovieTransfer(), new Movie() }; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   If you take a look at the foreach now, you can see it still actually do two things, calculate the price and display the price. We can do some more refactoring here by using the Sum extension method to calculate the total price of the movies:   static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfNormalMovie = movies.Where(m => m is Movie) .Sum(m => m.Price); int totalPriceOfTransferMovie = movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); foreach (var movie in movies.Where( m => m is Movie)) Console.WriteLine(movie.Price); foreach (var movie in movies.Where( m => m is MovieTransfer)) Console.WriteLine(movie.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now when the Movie object will hold the price, there is no need to use two separate foreach to display the price of the movies in the list, so we can use only one instead: foreach (var movie in movies) Console.WriteLine(movie.Price); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If we want to increase the Maintainability index we can use the Extract Method to move the Sum of the prices into two separate methods. The name of the method will explain what we are doing: static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); foreach (var movie in movies) Console.WriteLine(movie.Price); } private static int TotalPriceOfMovieTransfer(IEnumerable<Movie> movies) { return movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); } private static int TotalPriceOfMovie(IEnumerable<Movie> movies) { return movies.Where(m => m is Movie) .Sum(m => m.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now to the last thing, I love the ForEach method of the List<T>, but the IEnumerable<T> doesn’t have it, so I created my own ForEach extension, here is the code of the ForEach extension method: public static class LoopExtensions { public static void ForEach<T>(this IEnumerable<T> values, Action<T> action) { Contract.Requires(values != null); Contract.Requires(action != null); foreach (var v in values) action(v); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I will now replace the foreach by using this ForEach method: static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); movies.ForEach(m => Console.WriteLine(m.Price)); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The ForEach on the movies will now display the price of the movie, but maybe we want to display the name of the movie etc, so we can use Extract Method by moving the lamdba expression into a method instead, and let the method explains what we are displaying: movies.ForEach(DisplayMovieInfo); private static void DisplayMovieInfo(Movie movie) { Console.WriteLine(movie.Price); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now the refactoring is done! Here is the complete code:   class Program { static void Main(string[] args) { var movies = GetMovies(); int totalPriceOfMovie = TotalPriceOfMovie(movies); int totalPriceOfTransferMovie = TotalPriceOfMovieTransfer(movies); movies.ForEach(DisplayMovieInfo); } private static void DisplayMovieInfo(Movie movie) { Console.WriteLine(movie.Price); } private static int TotalPriceOfMovieTransfer(IEnumerable<Movie> movies) { return movies.Where(m => m is MovieTransfer) .Sum(m => m.Price); } private static int TotalPriceOfMovie(IEnumerable<Movie> movies) { return movies.Where(m => m is Movie) .Sum(m => m.Price); } private static IEnumerable<Movie> GetMovies() { return new List<Movie>() { new Movie(), new MovieTransfer(), new Movie() }; } } public class Movie { public virtual int Price { get { return 2; } } } public class MovieTransfer : Movie { public override int Price { get { return 3; } } } pulbic static class LoopExtensions { public static void ForEach<T>(this IEnumerable<T> values, Action<T> action) { Contract.Requires(values != null); Contract.Requires(action != null); foreach (var v in values) action(v); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I think the new code is much cleaner than the first one, and I love the ForEach extension on the IEnumerable<T>, I can use it for different kind of things, for example: movies.Where(m => m is Movie) .ForEach(DoSomething); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } By using the Where and ForEach extension method, some if statements can be removed and will make the code much cleaner. But the beauty is in the eye of the beholder. What would you have done different, what do you think will make the first example in the blog post look much cleaner than my results, comments are welcome! If you want to know when I will publish a new blog post, you can follow me on twitter: http://www.twitter.com/fredrikn

    Read the article

  • Ant: foreach loop

    - by user305801
    I'm trying to use the foreach loop in an Ant script but I get the message: Problem: failed to create task or type foreach Cause: The name is undefined. I don't understand why this doesn't work. It is not a 3rd party library. It is a standard task that would be part of the latest version of Ant (1.8). <target name="parse"> <echo message="The first five letters of the alphabet are:"/> <foreach param="instance" list="a,b,c,d,e"> </foreach> </target>

    Read the article

  • How to use a dynamic smarty variable in foreach loop

    - by P Kumar
    Hi, Can anyone tell me how to use dynamic variables in smarty foreach loop. I am trying to create a module in prestashop and m very close to get it done. here's my code: //file name index.php foreach($subCategories as $s) { $foo = intval($s['id_category']); $k = new Category($foo); $var1 = "subSubCategories.$foo"; $var1 = $k-getSubCategories(1); $smarty-assign(array('foo'.$foo = $var1)); } //file name:index.tpl {assign var=foo value=$foo$cat} //where $cat is a variable that counts the number of categories {if isset($foo) AND $foo} {foreach from=$foo item=subCategories name=homesubCategories} <p>{$subCategories.name}</p> {/foreach} {else} <p>{l s='test failed'}</p> {/if} I've exhausted all of my resources and knowledge and feeling quite helpless at this moment. so plz help me out.

    Read the article

  • Smarty - foreach loop 4 times and create a new list

    - by Harold
    I want to achieve a list like this with smarty. <ul> <li> <a>img1</a> <a>img2</a> <a>img3</a> <a>img4</a> </li> <li> <a>img5</a> <a>img6</a> <a>img7</a> <a>img8</a> </li> <li> <a>img9</a> <a>img10</a> <a>img11</a> <a>img12</a> </li> </ul> Using this sample code <ul class="bullet"> {foreach from=$manufacturers item=manufacturer name=manufacturer_list} {if $smarty.foreach.manufacturer_list.index < 4} <li class="{if $smarty.foreach.manufacturer_list.last}last_item{elseif $smarty.foreach.manufacturer_list.first}first_item{else}item{/if}"> <a href="{$link->getmanufacturerLink($manufacturer.id_manufacturer, $manufacturer.link_rewrite)}" title="{l s='More about' mod='blockmanufacturer'}{$manufacturer.name}"> <img src="{$img_manu_dir}{$manufacturer.id_manufacturer}.jpg"><span>{$manufacturer.name}<span></a> </li> {/if} {/foreach} First with given array $manufacturers it will loop inside a <li> max of 4 times and will create 4 <img>. And then, when it reach the 4th index, it will make a new <li> tag. Thanks for the help!

    Read the article

  • Foreach/For loop alternative lambda function?

    - by mamu
    We use for or foreach to loop through collections and process each entries. Is there any alternative in all those new lambda functions for collections in C#? Traditional way of doing foreach(var v in vs) { Console.write(v); } Is there anything like? vs.foreach(v => console.write(v))

    Read the article

  • How can I get cmake to find my boost installation

    - by BD at Rivenhill
    I have installed the most recent version of boost in /usr/local (with includes in /usr/local/boost and libraries in /usr/local/lib/boost) and I am now attempting to install Wt from source, but cmake (version 2.6) can't seem to find the boost installation. It tries to give helpful suggestions about setting BOOST_DIR and Boost_LIBRARYDIR, but I haven't been able to get it to work by tweaking these variables. The most recent error message that I get is that it can't find the libraries, but it seems to indicate that it is using "/usr/local/include" for the include path, which isn't correct (and I can't seem to fix it). Does anybody have a solution for this off the top of their head, or do I need to go mucking around inside cmake to figure it out?

    Read the article

  • Lucene boost: I need to make it work better

    - by zvikico
    I'm using Lucene to index components with names and types. Some components are more important, thus, get a bigger boost. However, I cannot get my boost to work properly. I sill get some components appear later (get worse score), even though they have a higher boost. Note that the indexing is done on one field only and I've set the boost to that field alone. I'm using Lucene in Java. I don't think it has anything to do with the field length. I've seen components with the same name (but different type) get the wrong score.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 21 22 23 24 25 26 27 28 29 30 31 32  | Next Page >