wrapper

问题 I searched it all over the web, but all the answers just consisted of the difference. I know the difference, but I don't understand the difference in their applications. For example, suppose we have to take two floating values, if we use double, we can easily compare using a==b , whereas if we use Double, we will have to use a.equals(b) . 回答1: There is more than that behind the scenes. One of the reasons is how the Collections API is developed in Java... Consider that you just can not do

问题 References to wrapper types like &Rc<T> and &Box<T> are invariant in T ( &Rc<T> is not a &Rc<U> even if T is a U ). A concrete example of the issue (Rust Playground): use std::rc::Rc; use std::rc::Weak; trait MyTrait {} struct MyStruct { } impl MyTrait for MyStruct {} fn foo(rc_trait: Weak<MyTrait>) {} fn main() { let a = Rc::new(MyStruct {}); foo(Rc::downgrade(&a)); } This code results in the following error: <anon>:15:23: 15:25 error: mismatched types: expected `&alloc::rc::Rc<MyTrait>`,

问题 While playing around with Java8's Streams-API, I stumbled over the following: To convert an array of primitive wrapper classe objects into a Stream I just have to call Stream.of(array) . But to convert an array of primitive data types, I have to call .of(array) from the corresponding wrapper (class) stream class (<-- that sounds silly). An example: final Integer[] integers = {1, 2, 3}; final int[] ints = {1, 2, 3}; Stream.of(integers).forEach(System.out::println); //That works just fine

问题 I'd like to write a simple wrapper for the python list type that forces it to start indexing at 1 instead of 0 . I've got a a fairly complex program based on some discrete probability distributions of duration data, with integer-length buckets, but I don't have any durations of less than 1. Anyway, it would greatly simplify a some significant portions of my code to be able to seamlessly index starting at 1. I was using a dict at first but I found several properties of them to be too

问题 How do I run the following piece of code that the output of function ftn4 using values from data frame I , is used by the newtonraphson function in combination with values from data frame R0 . I would like to store the output in a new data frame ( R ) of the same dimensions (ncol = 5, nrow = 5) as I an R0 . I am stuck, any ideas? Any hint greatly appreciated c = c(0.3) Ccf = c(0.3) Acf = c(3*10^-6) E = c(0.00006) Ke = c(1000) I = as.data.frame(matrix(sample(seq(150,300,0.1),25), ncol = 5,

问题 A friend of mine really likes using Joomla as a base for his websites. He also likes the power that Asp.Net has and can code in VB.Net. He wants to use Joomla as the "Master Page" and Asp.Net/VB.Net/SQL Server to handle the main business logic of the application. He is planning on using the Joomla Wrapper Module (an IFrame , joomla modules) to integrate the ASP.Net into the Joomla website. Joomla will be able to handle the security (users,roles,registration), menu (based on roles), static

问题 I am creating a C wrapper that can read types of data structures stored in text files. The interface should be that I can generate a unique id mapped to a unique data structure and modify through wrapper functions via the unique id. The problem is that I need to be able to generate a unique id to map. I would like to not use any external library. Is there any way to do this without any large overhead? 回答1: I guess that you are wanting the id to be (practically speaking) world-wide unique (so

问题 I'm writing classes which wrap around the TcpListener and TcpClient classes in VB. Currently here is my wrapper of the TcpListener class: Imports System.Net Imports System.Net.Sockets Imports System.Text Public Class XXXTcpServer : Inherits TcpListener Public name As String Public clients As List(Of TcpClient) Public maxClients As Integer = -1 ... Sub New(Optional ByVal name As String = "", Optional ByVal port As Int32 = 30000, Optional ByVal localAddr As IPAddress = Nothing) MyBase.New(If

问题 I have number of cpp files in unmanaged c++ , I want to access class methods of these files from vb .net using P\Invoke, For that i have write C wrapper for exposing class methods.Can anybody help me ,how to write a c wrapper around C++ code. I am copying some code of my files ,please help me writting c wrapper for these function. #include "StdAfx.h" #include "Verify.h" Verify::Verify(void) :_verified(false) { } Verify::~Verify(void) { } void Verify::SetVerified(bool value) { _verified =

问题 I've seen it mentioned sometimes that Repository Pattern is built into Entity Framework Code First via the DbSet and DbContext objects. However that leaves a few problems: 1) Injection - Hard to inject as there isn't a clear cut Interface 2) Mocking - Same as above 3) Multiple references to EnitityFramework.dll - Let's say I create my Code First in it's own assembly/project and then want to reference that in another place I also have to reference entityFramework.dll without some wrapper