题目内容

回调(Callback)函数是面向过程的程序设计语言中常用的一种机制,而设计模式中的(1)模式就是回调机制的一个面向对象的替代品。该模式的意图是(2)。 2()

A. 使原本由于接口不兼容而不能一起工作的那些类可以一起工作
B. 将一个请求封装为一个对象,从而可用不同的请求对客户进行参数化,将请求排队或记录请求日志,支持可撤销的操作
C. 定义对象间的一种一对多的依赖关系,当一个对象的状态发生改变时,所有依赖于它的对象都得到通知并被自动更新
D. 使算法可独立于使用它的客户而变化

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关于Windows操作系统中DHCP服务器的租约,下列说法中错误的是()

A. 默认租约期是8天
B. 客户端一直使用DHCP服务器分配给它的IP地址,直至整个租约期结束才开始联系更新租约
C. 当租约期过了一半时,客户端将与提供IP地址的DHCP服务器联系更新租约
D. 在当前租约期过去87.5%时,如果客户端与提供IP地址的DHCP服务器联系不成功,则重新开始IP租用过程

TCP是互联网中的 (12) 协议,使用 (13) 次握手协议建立连接。 (13)应选入()。

A. 1
B. 2
C. 3
D. 4

传输一幅分辨率为640x480,6.5万色的照片(图像),假设采用数据传输速度为56Kbps,大约需要()秒钟。

A. 34.82
B. 42.86
C. 85.71
D. 87.77

Extreme Programming (XP) is a discipline of software development with (14) of simplicity, communication, feedback and courage. Successful software development is a teameffort - not just the development team, but the larger team consisting of customer,management and developers. XP is a simple process that brings these people together andhelps them to succeed together. XP is aimed primarily at object-oriented projects using teamsof a dozen or fewer programmers in one location. The principles of XP apply to any (15) project that needs to deliver quality software rapidly and flexibly.An XP project needs a(an) (16) customer to provide guidance. Customers, programmers, managers, are all working (17) to build the system that’sneedeD. Customers - those who have software that needs to be developed - will learn simple,effective ways to (18) what they need, to be sure that they are getting what they need,and to steer the project to success. (17)应选入()。

A. together
B. by themselves
C. separately
D. alone

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