Is there a container adapter that would reverse the direction of iterators so I can iterate over a container in reverse with range-based for-loop? With explicit iterators I would convert this: for (auto i = c.begin(); i != c.end(); ++i) { ... into this: for (auto i = c.rbegin(); i != c.rend(); ++i) { ... I want to convert this: for (auto& i: c) { ... to this: for (auto& i: std::m
有没有一个容器适配器可以颠倒迭代器的方向，所以我可以通过基于范围的for-loop来反转容器的相反方向？ 使用显式迭代器，我会将其转换为： for (auto i = c.begin(); i != c.end(); ++i) { ... 进入这个： for (auto i = c.rbegin(); i != c.rend(); ++i) { ... 我想转换这个： for (auto& i: c) { ... 对此： for (auto& i: std::magic_reverse_adapter(c)) { ... 有这样的事情吗，还是我必须自己写？ 实际上
I know that in general the life time of a temporary in a range-based for loop is extended to the whole loop (I've read C++11: The range-based for statement: "range-init" lifetime?). Therefore doing stuff like this is generally OK: for (auto &thingy : func_that_returns_eg_a_vector()) std::cout << thingy; Now I'm stumbling about memory issues when I try to do someth
我知道一般来说，基于范围的for循环中的临时生命周期扩展到整个循环（我读过C ++ 11：基于范围的for语句：“range-init”生命周期？）。 因此，做这样的事情通常是可以的： for (auto &thingy : func_that_returns_eg_a_vector()) std::cout << thingy; 当我尝试做一些我认为与Qt的QList容器类似的东西时，现在我正在徘徊在内存问题上： #include <iostream> #include <QList> int main() { for (au
Suppose I have a class T where T has no virtual functions. T instances have no state. T has static member instances of itself. T itself has no other state. Can the C++ static initialization fiasco ruin my program? I don't think so because even if one of the static instances is not initialized before use, that should not matter because T objects are stateless. I'm interested i
假设我有一个类T在哪里 T没有虚拟功能。 T实例没有状态。 T有自己的静态成员实例。 T本身没有其他国家。 C ++静态初始化失败可以毁掉我的程序吗？ 我不这么认为，因为即使其中一个静态实例在使用之前未被初始化，也不应该担心，因为T对象是无状态的。 我有兴趣为类枚举类做这样的事情： // Switch.h class Switch { public: static Switch const ON; static Switch const OFF; bool operator== (Switc
Nowdays I just want to use FFTW3 on iOS, since I've compiled it successfully into i386 version which is used by the iOS simulator, the rest work is to compile it into armv6(or v7) version and lipo these two versions together,below is my incorrect configure: ./configure CC=/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-gcc-4.2.1 LD=/Developer/Platforms/iPhoneOS.p
现在我只想在iOS上使用FFTW3，因为我已经成功将它编译成iOS模拟器使用的i386版本，剩下的工作是将它编译成armv6（或v7）版本，并将这两个版本一起编译是我的错误配置： ./configure CC = / Developer / Platforms / iPhoneOS.platform / Developer / usr / bin / arm-apple-darwin10-gcc-4.2.1 LD = / Developer / Platforms / iPhoneOS.platform / Developer / usr / bin / ld CCFLAGS =“ - I /开发人员/平台/iPhoneOS.platf
I have an edge list of undirected graph 1 2 3 4 5 6 I need to perform Page rank using MPI on this graph Efficiency is of most importance. My question is whats the most efficient way to read large graphs like this and store them in an adjacency list in C++. The said graph contain million nodes and even more edges.
我有一个无向图的边界列表 1 2 3 4 5 6 我需要在此图表上使用MPI执行Page rank效率是最重要的。 我的问题是什么是读取这样的大图的最有效的方法，并将它们存储在C ++的邻接列表中。 所述图形包含百万个节点和更多的边缘。
I have a undirected graph where the nodes are stored in a flat array. Now I am looking for a data structure for the edges. It should have constant time complexity for getting all edges of a given node. An edge contains two node indices and additional information such as a weight. The only way I see is duplicating the data, one sorted by the left node and another sorted by the right node. ve
我有一个无向图，其中节点存储在一个平面阵列中。 现在我正在寻找边缘的数据结构。 它应该具有恒定的时间复杂度，以获得给定节点的所有边。 边缘包含两个节点索引和附加信息，如权重。 我看到的唯一方法是复制数据，一个按左节点排序，另一个按右节点排序。 vector<vector<int>> left, right; 但我想防止重复边缘。 这听起来像你只是想要一个邻接表的表示。 在这种表示中，每个节点将存储其所有连接边的
I am planning on representing a fairly large, sparse, undirected graph structure in C++. This will be of the order of 10,000+ vertices, with each vertex having a degree of around 10. I have read some background on representing graphs as adjaciency matrices or lists, but neighther of them seem suitable for what I want to do. In my scenario: Each edge in the graph will have some properties (n
我正计划在C ++中表示一个相当大，稀疏，无向的图结构。 这将是10000个顶点的数量级，每个顶点的度数大约为10。 我已经阅读了关于表示图形作为相邻矩阵或列表的一些背景，但其中的更近似于我想要做的事。 在我的场景中： 图形中的每条边都会附加一些属性（数值） 在初始图形创建之后，边缘可以被删除，但从未创建 顶点永远不会被创建或删除 图上的主要查询操作将是对于边E的查找，以及关于哪些其他边连接到边。 这
What would be the best strategy to build a boost graph that holds both directed and undirected edges? I want to model a social network, where nodes represent people, and edges represent relationships. Some relationships are undirected (BrotherOf), while other are directed (FatherOf). I need something like in_edges, out_edges and undirected_edges iterators. Edit: Since I need to deal with
建立一个兼有有向边和无向边的推进图的最佳策略是什么？ 我想建立一个社交网络，其中节点代表人，边代表关系。 一些关系是无向的（BrotherOf），而另一些则是直接的（FatherOf）。 我需要像in_edges，out_edges和undirected_edges迭代器。 编辑： 由于我需要处理非常大的图，我想要一种在内存消耗和算法执行速度方面都有效的方法。 您可以简单地将其表示为有向图。 然后可以通过在两个方向上用有向边替换它来表示无
Is there any way to easily implement a proxy class pattern in C++? Not using AspectC++ or other heavy tools, just built-in macro or templates. Explaining what I want: class base_class { public: virtual void method_one() { ... } virtual void method_two() { ... } } class class_proxy : base_class { protected: void before_any_method_call() { do stuff }; void after_any_method_c
有什么方法可以在C ++中轻松实现代理类模式？ 不使用AspectC ++或其他繁重的工具，只使用内置的宏或模板。 解释我想要什么： class base_class { public: virtual void method_one() { ... } virtual void method_two() { ... } } class class_proxy : base_class { protected: void before_any_method_call() { do stuff }; void after_any_method_call(std::exception* ex) { do stuff } } 这是场景
Is it possible to hide some member functions in a template class? Let's imagine we have something like: template <class T> class Increment { public: void init(T initValue) { mValue = initValue; } T increment() { ++mValue; } T increment(T delta) { mValue += delta; } private: T mValue; }; The objective is to use this
是否有可能隐藏模板类中的一些成员函数？ 让我们想象我们有这样的东西： template <class T> class Increment { public: void init(T initValue) { mValue = initValue; } T increment() { ++mValue; } T increment(T delta) { mValue += delta; } private: T mValue; }; 目标是以某种方式使用这个类，在某些情况下，我们只能看到increment（）