implementation

Can a member of a class be named the same name as its type (another class)?

由 元气小坏坏 提交于 2019-11-28 07:23:33
问题 Trying to compile the following code on different compilers gives me two different results: struct S{}; struct T{S S;}; int main(){} As you can see, inside T , I have an object named the same as the previously defined class S . On GCC 4.7.2, I get the following error pertaining to the S S; declaration inside T : error: declaration of 'S T::S' [-fpermissive] error: changes meaning of 'S' from 'struct S' [-fpermissive] However, moving it outside of the class (or into main ) works fine: struct S

Enumerable.Range implementation

由 ﹥＞﹥吖頭↗ 提交于 2019-11-28 06:36:44
问题 What is the precise implementation of Enumerable.Range in .Net; preferable .Net 4? Is it a yielded for-loop? A custom implementation (IEnumerable, IEnumerator) or? 回答1: The accepted answer on this question should give you the answer: public static class Enumerable { public static IEnumerable<int> Range(int start, int count) { var end = start + count; for(var current = start; current < end; ++current) { yield return current; } } } This isn't the exact code, as there is a lot of error checking

Find Minimum Number of Swaps to Sort an Array [duplicate]

由 元气小坏坏 提交于 2019-11-28 06:04:10
问题 This question already has an answer here: Compute the minimal number of swaps to order a sequence 13 answers Given an array with distinct elements, what is the minimum number of swap needed to sort it? For example, the array [4, 2, 1, 3] needs at least 2 swaps (e.g. swapping 4 and 1 then 4 and 3). This is my approach: B = sort(copy(A)) for i = 0 ... len(A) - 1 if A[i] != B[i] find j such that A[j] == B[i] swap(A[i], A[j]) Is my approach corrert? Is there another way to solve it? 回答1: That

Where can I find useful R tutorials with various implementations?

由 丶灬走出姿态 提交于 2019-11-28 05:08:22
I'm using R language and the manuals on the R site are really informative. However, I'd like to see some more examples and implementations with R which can help me develop my knowledge faster. Any suggestions? I'll mention a few that i think are excellent resources but that i haven't seen mentioned on SO. They are all free and freely available on the Web (links supplied). Data Analysis Examples A collection of individual examples from the UCLA Statistics Dept. which you can browse by major category (e.g., "Count Models", "Multivariate Analysis", "Power Analysis") then download examples with

Standard container re-allocation multipliers across popular toolchains

由 这一生的挚爱 提交于 2019-11-28 01:57:33
Containers like std::basic_string and std::vector perform automatic re-allocations when internal capacity runs out. The standard specifies that, after a re-allocation, .capacity() >= .size() . What are some of the actual multipliers used by mainstream toolchains when performing re-allocations? Update So far, I have: Dinkumware: 1.5 (ships with MSVS and possibly ICC) GNU libstdc++: 2 (ships with GCC and possibly ICC) RW/Apache stdcxx: 1.618 (aka φ) STLport: 2 New answer for an old question. Rationale: The answer can be answered programatically, and with online compilers, relatively easily. Here

Performance of Dijkstra's algorithm implementation

由 早过忘川 提交于 2019-11-28 00:59:05
问题 Below is an implementation of Dijkstra's algorithm I wrote from the pseudocode in the Wikipedia article. For a graph with about 40 000 nodes and 80 000 edges, it takes 3 or 4 minutes to run. Is that anything like the right order of magnitude? If not, what's wrong with my implementation? struct DijkstraVertex { int index; vector<int> adj; vector<double> weights; double dist; int prev; bool opt; DijkstraVertex(int vertexIndex, vector<int> adjacentVertices, vector<double> edgeWeights) { index =

Register an object creator in object factory

由 两盒软妹~` 提交于 2019-11-27 22:37:36
I have the convenient object factory template that creates objects by their type id names. The implementation is pretty obvious: ObjectFactory contains the map from std::string to object creator function. Then all objects to be created shall be registered in this factory. I use the following macro to do that: #define REGISTER_CLASS(className, interfaceName) \ class className; \ static RegisterClass<className, interfaceName> regInFactory##className; \ class className : public interfaceName where RegisterClass is template<class T, class I> struct RegisterClass { RegisterClass() { ObjectFactory<I

Adding Cocos2D only to already existing project?

由 北慕城南 提交于 2019-11-27 21:02:15
问题 I already have a project that is 90% done and I want to add Cocos2D ONLY to it. I do not need Box2D or Chipmunk. How would I do this? What files do I add? I really need this done, so in the end ill offer a bounty if needed. Thanks! 回答1: To start the easier way to add Cocos2d into your project is to follow these lines: Import the Cocos2d files into your project like the picture below: Then import the "FontLabel" folder which is located into the "external" folder (Into the Cocos2d library) like

C++ assert implementation in assert.h

由 浪尽此生 提交于 2019-11-27 17:46:49
问题 00001 /* assert.h 00002 Copyright (C) 2001, 2003 Free Software Foundation, Inc. 00003 Written by Stephane Carrez (stcarrez@nerim.fr) 00004 00005 This file is free software; you can redistribute it and/or modify it 00006 under the terms of the GNU General Public License as published by the 00007 Free Software Foundation; either version 2, or (at your option) any 00008 later version. 00009 00010 In addition to the permissions in the GNU General Public License, the 00011 Free Software Foundation

Conflicting implementations of trait in Rust

由 扶醉桌前 提交于 2019-11-27 16:04:03
I want to implement a custom trait for &'a str and for integer numbers up to i32 , but Rust does not allow me to: use std::convert::Into; pub trait UiId { fn push(&self); } impl<'a> UiId for &'a str { fn push(&self) {} } impl<T: Into<i32>> UiId for T { fn push(&self) {} } fn main() {} This fails to compile with the following error: error[E0119]: conflicting implementations of trait `UiId` for type `&str`: --> src/main.rs:11:1 | 7 | impl<'a> UiId for &'a str { | ------------------------- first implementation here ... 11 | impl<T: Into<i32>> UiId for T { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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