Microsoft Visual C＋＋4.0特色一二

C或者C＋十是当今最为重要的编程语言，其作为开发工具一向是大软件厂商的必争之地。以往BOrland的产品总被公认略胜一筹。但自93年推出VisualC＋十以来，Microsoft渐渐地占了上风，进入96年后，Microsoft又接踵推出了VC＋＋4．0、4．正和4．2版本，使它的竞争优势进一步得到了加强。下面介绍的VC＋＋4．X版的新功能，虽然只是其中的一部分，但仍能对它的强大功能有所了解。DeveloperStudio——既熟悉又陌生的开发环境VC＋＋4．0的最大变化莫过于它采用了一个独立于VC＋＋，又与VC＋十紧密集成的新开发环境，即DeveloperStudio。…     

VC＋＋程序设计教学探讨

笔者结合自己的实际教学经验,对VC＋＋程序设计语言课程的教学进行了比较深入的探讨。     

BC＋＋4.0,4.5下的Window程序设计快速入门

高性能微机和内存条价格大幅度下降,中文Windows3.1,3.2与中文Windows95在国内开始普及,越来越多的人都希望能用C语言作些Windows应用程序的开发工作;因为Windows把它能做的事(诸如内存管理、打印机、鼠标、显示器、图形库、通讯库等等)都做了,Windows应用程序的开发者不必再为这些事操心,所以应该说比DOS应用程序的开发     

PowerBuilder中的Watcom C＋＋Builder的应用

我们用PowerBuilder开发应用系统,多数可以用PowerBuilder自身提供的函数实现,但遇到图像处理、复杂的逻辑和科学运算时,单靠PowerBuilder的自身功能就有些力不从心了。如果选用C或C++语言来实现极为容易,可喜的是PowerBuilder内嵌有Watcom C++Class Builder,它是一种C++语言编译器,选用它来解决PowerBuilder自身不易实现的功能,显得十分简单,使用也较方便。     

ConC++:C++的一种并发扩充语言

提出一种对Ｃ＋＋进行并发扩充的语言ＣｏｎＣ＋＋．ＣｏｎＣ＋＋是一个并发面向对象语言,它采用并发类和保护类的机制支持并发,并发类有一个主动函数,一旦对象被创建,这个主动函数就开始执行;保护类封装了一组数据和对数据的操作,它没有自己的线程,而且是用来实现对并发类对象的同步、互斥和通信,这种集中控制对象的并发的方法体现了对象的自治性特点,减少了上下切换和死锁发生的可能,从而提高了程序的性能。     

Visual C++.NET应用与开发系列讲座--托管C++程序设计

作为.NET的最新特性组成部分,Microsoft.NET Framework(框架)是一个用于构建,部署和运行Web服务及应用程序的平台.它包含三个主要部分:通用语言运行时、一组层次化的统一的类库和组件化版本的动态服务器主页(称为ASP.NET).     

在C＋＋Builder工程里使用Visual C＋＋DLL——第2部分：C＋＋类

上一篇文章为MSVC DLL创建一个Borland兼容的引入库。主要的难点在于MSVC和Borland使用的函数命名格式不同。举例来说,Borland认为_cdecl函数在它们的开头有一个下划线,但MSVC没有。幸运的是,你可以用Borland命令行实用工具克服名称的不同,这些工具有TDUMP、IMPLIB、IMPDEF、和     

C＋＋Builder与Oracle数据库连接的常见问题及解决方法

Insprise(原Borband)公司的C++集成开发环境C++Builder是开发客户/服务器应用和Internet/Intranet应用的优秀工具。它通过无缝地集成数据库设计部件和可视化用户接口的创建,极大地降低了开发数据库应用的复杂度。C++Builder使用ODBC或自带的高速驱动程序与数据库连接,支持Oracle、MS SQL Server、DB2、Sybase和Access等几乎所有的数据库产品。与VB、VC++和PB等其他开发工具相比,C++Builder最突出的优点之一是可     

DC＋＋：具有分布并行机制的C＋＋

ＤＣ＋＋是一种具有分布并行设施的面对向对象编程语言。它是由面向对象语言Ｃ＋＋向上兼容扩充得到的。本文介绍ＤＣ＋＋语言的设计与实现。     

Suslin’s algorithms for reduction of unimodular rows

A well-known lemma of Suslin says that for a commutative ring $A$ if $(v_1\left(X\right),\dots ,v_n\left(X\right))\in {\left(A\left[X\right]\right)}^n$ is unimodular where $v_1$ is monic and $n\ge 3$, then there exist ${\gamma }_1,\dots ,{\gamma }_{\ell }\in E_{n-1}\left(A\left[X\right]\right)$ such that the ideal generated by $\mathrm{Res}(v_1,e_1.{\gamma }_1{}^t(v_2,\dots ,v_n)),\dots ,\mathrm{Res}(v_1,e_1.{\gamma }_{\ell }{}^t(v_2,\dots ,v_n))$ equals $A$. This lemma played a central role in the resolution of Serre’s Conjecture. In the case where $A$ contains a set $E$ of cardinality greater than $deg{v}_1+1$ such that $y-y^{\prime }$ is invertible for each $y\ne y^{\prime }$ in $E$, we prove that the ${\gamma }_i$ can simply correspond to the elementary operations $L_1\to L_1+y_i{\sum }_{j=2}^{n-1}{u}_{j+1}{L}_j$, $1\le i\le \ell =deg{v}_1+1$, where $u_1{v}_1+\cdots +u_n{v}_n=1$. These efficient elementary operations enable us to give new and simple algorithms for reducing unimodular rows with entries in $K[X_1,\dots ,X_k]$ to ${}^t(1,0,\dots ,0)$ using elementary operations in the case where $K$ is an infinite field. Another feature of this paper is that it shows that the concrete local–global principles can produce competitive complexity bounds.     

Boundedness in the higher-dimensional quasilinear chemotaxis-growth system with indirect attractant production

This paper deals with the following quasilinear chemotaxis-growth system

in a smoothly bounded domain $\Omega ?{\mathbb{R}}^n(n\ge 3)$ under zero-flux boundary conditions. The parameters $\mu ,\delta$ and $\tau$ are positive and the diffusion function $D\left(u\right)$ is supposed to generalize the prototype $D\left(u\right)\ge D_0{u}^{\theta }$ with $D_0>0$ and $\theta \in \mathbb{R}$. Under the assumption $\theta >1?\frac{4}{n}$, it is proved that whenever $\mu >0$, $\tau >0$ and $\delta >0$, for any given nonnegative and suitably smooth initial data ($u_0$, $v_0$, $w_0$) satisfying $u_0?0$, the corresponding initial–boundary problem possesses a unique global solution which is uniformly-in-time bounded. The novelty of the paper is that we use the boundedness of the $\left|\right|v(?,t)|{|}_{W^{1,s}\left(\Omega \right)}$ with $s\in [1,\frac{2n}{n?2})$ to estimate the boundedness of $\left|\right|?v(?,t)|{|}_{L^{2q}\left(\Omega \right)}(q>1)$. Moreover, the result in this paper can be regarded as an extension of a previous consequence on global existence of solutions by Hu et al. (2016) under the condition that $D\left(u\right)\equiv 1$ and $n=3$.     

Finite time blow-up for a class of parabolic or pseudo-parabolic equations

In this paper, we study the initial boundary value problem for a class of parabolic or pseudo-parabolic equations:

$u_t?a\Delta u_t?\Delta u+bu=k\left(t\right)|u{|}^{p?2}u,(x,t)\in \Omega \times (0,T),$

where $a\ge 0$, $b>?{?}_1$ with ${?}_1$ being the principal eigenvalue for $?\Delta$ on $H_0^1\left(\Omega \right)$ and $k\left(t\right)>0$. By using the potential well method, Levine’s concavity method and some differential inequality techniques, we obtain the finite time blow-up results provided that the initial energy satisfies three conditions: (i) $J(u_0;0)<0$; (ii) $J(u_0;0)\le d\left(\infty \right)$, where $d\left(\infty \right)$ is a nonnegative constant; (iii) $0<J(u_0;0)\le C\rho \left(0\right)$, where $\rho \left(0\right)$ involves the $L^2$-norm or $H_0^1$-norm of the initial data. We also establish the lower and upper bounds for the blow-up time. In particular, we obtain the existence of certain solutions blowing up in finite time with initial data at the Nehari manifold or at arbitrary energy level.     

Existence and multiplicity of solutions for a nonlocal problem with critical Sobolev exponent

In this work, we are interested in considering the following nonlocal problem

where $\Omega ?{\mathbb{R}}^N(N\ge 4)$ is a smooth bounded domain, $a\ge 0,b>0,1<q<2,\mu ,\lambda >0$ and $2^1=\frac{2N}{N?2}$ is the critical Sobolev exponent. By using the variational method and the critical point theorem, some existence and multiplicity results are obtained.     

A new approach toward stabilization in a two-species chemotaxis model with logistic source

This paper aims at providing an alternative approach to study global dynamic properties for a two-species chemotaxis model, with the main novelty being that both populations mutually compete with the other on account of the Lotka–Volterra dynamics. More precisely, we consider the following Neumann initial–boundary value problem

in a bounded domain $\Omega ?{\mathbb{R}}^n,n\ge 1$, with smooth boundary, where $d_1,d_2,d_3,{\chi }_1,{\chi }_2,{\mu }_1,{\mu }_2,a_1,a_2$ are positive constants.When $a_1\in (0,1)$ and $a_2\in (0,1)$, it is shown that under some explicit largeness assumptions on the logistic growth coefficients ${\mu }_1$ and ${\mu }_2$, the corresponding Neumann initial–boundary value problem possesses a unique global bounded solution which moreover approaches a unique positive homogeneous steady state $(u^1,v^1,w^1)$ of above system in the large time limit. The respective decay rate of this convergence is shown to be exponential.When $a_1\ge 1$ and $a_2\in (0,1)$, if ${\mu }_2$ is suitable large, for all sufficiently regular nonnegative initial data $u_0$ and $v_0$ with $u_0?0$ and $v_0?0$, the globally bounded solution of above system will stabilize toward $(0,1,1)$ as $t\to \infty$ in algebraic.     

Global and blow-up solutions for nonlinear parabolic equations with Robin boundary conditions

In this paper we discuss the blow-up for classical solutions to the following class of parabolic equations with Robin boundary condition: $\{\begin{array}{cc}{\left(b\left(u\right)\right)}_t=??\left(g\left(u\right)?u\right)+f\left(u\right)\hfill & \text{in }\Omega \times (0,T)\text{,}\hfill \\ \frac{?u}{?n}+\gamma u=0\hfill & \text{on }?\Omega \times (0,T)\text{,}\hfill \\ u(x,0)=h\left(x\right)\ge 0\hfill & \text{in }\overline{\Omega }\text{,}\hfill \end{array}$ where $\Omega$ is a bounded domain of ${\mathbb{R}}^N(N\ge 2)$ with smooth boundary $?\Omega$. By constructing some appropriate auxiliary functions and using a first-order differential inequality technique, we derive conditions on the data which guarantee the blow-up or the global existence of the solution. For the blow-up solution, a lower bound on blow-up time is also obtained. Moreover, some examples are presented to illustrate the applications.     

会计信息化系统注册码设计创意

在会计信息化系统中,密码（口令）与注册码作用不同,密码一般是开发者预设初值,用户购买时都一样,用户使用时修改,以便分工划分权限。而注册码是开发者根据用户某属性预设,所有的用户都不同,目的是防止非法使用。注册码设计比密码设计略复杂,这方面的内容公开的很少,本文进行介绍。     

The constraints for the thermodynamic parameters of the type order–disorder transformation

A mathematical analysis of the constraints on the thermodynamic parameters of the compound energy formalism for an ${(A,B)}_m{(A,B)}_n\leftrightarrow {(A,B)}_{m+n}$ type order–disorder transformation is studied. Both the ordered phase and the disordered phase can be described using the two-sublattice model after the formula ${\left(A_{y_A^{\prime }}{B}_{y_B^{\prime }}\right)}_m{\left(A_{y_a^{″}}{B}_{y_B^{″}}\right)}_n$, with $y_i^{\prime }=y_i^{″}(i=A,B)$ for the disordered phase and $y_i^{\prime }\ne y_i^{″}$ for the ordered phase. The constraints between the parameters for the ordered state were derived. The thermodynamic characteristics of the transformation are illustrated using a mathematical method and the validity of the model and the constraints is tested.     

Approximation algorithms for the Weighted t-Uniform Sparsest Cut and some other graph partitioning problems

We study the Weighted t-Uniform Sparsest Cut (Weighted t-USC) and other related problems. In an instance of the Weighted t-USC problem, a parameter t and an undirected graph $G=(V,E)$ with edge-weights $w:E\to {\mathbb{R}}_{\ge 0}$ and vertex-weights $\eta :V\to {\mathbb{R}}_{+}$ are given. The goal is to find a vertex set $S\subseteq V$ with $|S|\le t$ while minimizing $w(S,V\backslash S)/\eta (S)$, where $w(S,V\backslash S)$ is the total weight of the edges with exactly one endpoint in S and $\eta (S)={\sum }_{v\in S}\eta (v)$. For this problem, we present a $(O(\log t),1+ϵ)$ factor bicriteria approximation algorithm. Our algorithm outperforms the current best algorithm when $t=n^{o(1)}$. We also present better approximation algorithms for Weighted ρ-Unbalanced Cut and Min–Max k-Partitioning problems.