c++ - Why use bind instead of function call? -

-

what advantage of using boost::bind in case

std::for_each(participants_.begin(), participants_.end(),     boost::bind(&chat_participant::deliver, _1, boost::ref(msg)));

instead of

for(iterator actual = participants_.begin(); actual != participants_.end(); ++actual)     (*actual)->deliver(msg);



link whole code (this simple server example provided boost tutorials).

i think it's pre c++11, algorithms recommended on plain for-loops things. in theory, it's easier understand purpose of code, don't have understand whole loop implementation first. for_each perhaps extreme though, since for-loop implementation simplest.

before lambda functions, 'boost::bind' requirement if wanted use algorithm without defining custom functor.

nowadays, range-based loops, you'd this:

for (auto& participant : participants)     participant->deliver(msg);

algorithms still better more complicated loops though (especially don't have use 'boost::bind').


Comments

Post a Comment

Popular posts from this blog

java - WrongTypeOfReturnValue exception thrown when unit testing using mockito -

-
my test list<person> mylist; @test public void testisvalidperson() { mylist = new arraylist<person>(); mylist.add(new person("tom")); when(persondao.get(person)).thenreturn(mylist); when((persondao.get(person)).isempty()).thenreturn(false);//------exception thrown boolean result = service.isvalid("tom"); assertfalse(result); } method tested: public boolean isvalid(string person){ persondao = new persondao(); person personobj = new person(person); return (persondao.get(person).isempty())?false : true; } exception thrown: org.mockito.exceptions.misusing.wrongtypeofreturnvalue: boolean cannot returned get() get() should return list *** if you're unsure why you're getting above error read on. due nature of syntax above problem might occur because: 1. exception *might* occur in wrongly written multi-threaded tests. please refer mockito faq on limitations of concurrency testing. 2. sp...
Read more

c++11 - Intel compiler and "cannot have an in-class initializer" when using constexpr -

-
the following test program compiles , runs fine g++. intel icpc (14.0.2) compile , run if use explicit type double instead of template. template version icpc produces error: icpc -g -o2 -i. -std=c++0x -c main.cc -o main.o main.cc(10): error: member of type "const t [9]" cannot have in-class initializer static constexpr t dx_[9] = { test code template<typename t> class myclass { public: static constexpr t dx_[9] = { 1.5, 2.0, -0.5, -0.5, 0.0, 0.5, 0.5, -2.0, -1.5 }; }; template<typename t> constexpr t myclass<t>::dx_[9]; int main(int argc, char *argv[]) { return 0; } // main why receiving error "cannot have in-class initializer" when using constexpr ? this bug of intel compiler, submitted intel , fixed in future versions. also see multiple constexpr bugs , sfinae bug intel c++ compiler 15 , method constexpr bug c++ compiler 15 on intel forums.
Read more

rest - Spring boot: Request method 'PUT' not supported -

-
i getting request method 'put' not supported error on hitting put method on restful api upload file. following information uploaded ticket. client log restcontroller spring boot app config tomcat log pom.xml 1. client log $ curl -x put -t "/cygdrive/c/a/documents/test.pptx" http://localhost:8080/piranha-storage-service/buckets/gnaval.bucket1/test.pptx <html><head><title>apache tomcat/7.0.52 - error report</title><style><!--h1 {font-family:tahoma,arial,sans-serif;color:white;background-color:#525d76;font-size:22px;} h2 {font-family:tahoma,arial,sans-serif;color:white;background-color:#525d76;font-size:16px;} h3 {font-family:tahoma,arial,sans-serif;color:white;background-color:#525d76;font-size:14px;} body {font-family:tahoma,arial,sans-serif;color:black;background-color:white;} b {font-family:tahoma,arial,sans-serif;color:white;background-color:#525d76;} p {font-family:tahoma,arial,sans-serif;background:white;co...
Read more