inserter

Improving efficiency of std::copy() with back_inserter() or inserter()

由 给你一囗甜甜゛ 提交于 2019-12-19 09:17:13
问题 back_inserter and insert_iterator are very handy, but they're also very inefficient! When you're appending char s, for example, there is a great deal of overhead for every element when you're copy ing, when in many situations, there really doesn't need to be. Is there a way to make them more efficient? 回答1: Yes, you can define a new version of std::copy which can hijack optimizable calls. :) Below is an example (or "hack", if you prefer to see the glass half-empty) for Visual C++ and GCC. On

Error: Overloading ambiguity between "std::copy

由 风格不统一 提交于 2019-12-11 06:59:21
问题 I have a code like below: #include<set> #include<iterator> std::set<std::string> s1; std::set<std::string> s2; std::set<std::string> myresult; void some_func() { std::set_difference(s1.begin(), s1.end(), s2.begin(), s2.end(),std::inserter(myresult,myresult.begin())); } This gives me compilation error: /export/SunStudio/SUNWspro/prod/include/CC/Cstd/./algorithm.cc", line 2161: Error: Overloading ambiguity between "std::copy<__rwstd::__rb_tree<std::string, std::string, __rwstd::__ident<std:

Improving efficiency of std::copy() with back_inserter() or inserter()

由 北慕城南 提交于 2019-12-01 06:23:52
back_inserter and insert_iterator are very handy, but they're also very inefficient! When you're appending char s, for example, there is a great deal of overhead for every element when you're copy ing, when in many situations, there really doesn't need to be. Is there a way to make them more efficient? Yes, you can define a new version of std::copy which can hijack optimizable calls. :) Below is an example (or "hack", if you prefer to see the glass half-empty) for Visual C++ and GCC. On my personal computer (I use VC++ 2010), the code below makes calls ten times faster ! A benchmark for GCC's

Inserters for STL stack and priority_queue

由 元气小坏坏 提交于 2019-11-30 08:26:52
问题 std::vector , std::list and std::deque have std::back_inserter , and std::set has std::inserter . For std::stack and std::priority_queue I would assume the equivalent inserter would be a push() but I can't seem to find the correct function to call. My intent is to be able to use the following function with the correct insert iterator: #include <string> #include <queue> #include <iterator> template<typename outiter> void foo(outiter oitr) { static const std::string s1 ("abcdefghji"); static
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