Software entities are more complex for t

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问题 Software entities are more complex for their size than perhaps any other human construct,because no two parts are alike(at least above the statement level).If they are,we make the two similar parts into one,a(1),open or closed.In this respect software systems differ profoundly from computers,buildings,or automobiles,where repeated elements abound.Digital computers are themselves more complex than most things people build;they have very large numbers of states.This makes conceiving,describing,and testing them hard.Software systems have orders of magnitude more(2)than computers do.Likewise,a scaling-up of a software entity is not merely a repetition of the same elements in larger size;it is necessarily an increase in the number of different elements.In most cases,the elements interact with each other in some(3)fashion,and the complexity of the whole increases much more than linearly.The complexity of software is a(an)(4)property,not an accidental one.Hence descriptions of a software entity that abstract away its complexity often abstract away its essence.Mathematics and the physical sciences made great strides for three centuries by constructing simplified models of complex phenomena,deriving properties from the models,and verifying those properties experimentally.This worked because the complexities(5)in the models were not the essential properties of the phenomena.It does not work when the complexities are the essence.Many of the classical problems of developing software products derive from this essential complexity and its nonlinear increases with size.Not only technical problems but management problems as well come from the complexity.问题1选项A.taskB.jobC.subroutineD.program问题2选项A.statesB.partsC.conditionsD.expressions问题3选项A.linearB.nonlinearC.parallelD.additive问题4选项A.surfaceB.outsideC.exteriorD.essential问题5选项A.fixedB.includedC.ignoredD.stabilized

选项

答案 CABDC

解析 软件实体的尺寸比任何其他人类构造更复杂,因为没有两个部分相同(至少在语句级上)。如果是,我们将两个相似的部分分成一个,一个(1),开放或关闭。在这方面,软件系统与计算机,建筑物或汽车有着深刻的区别,其中重复的元素很多。
数字电脑本身比大多数人理解的很多情况都要更复杂。这使得构思,描述和测试他们非常复杂。软件系统比计算机更多(2)数量级。
同样地,软件实体的放大不仅仅是较大尺寸的相同元素的重复;必然增加不同要素的数量。在大多数情况下,这些元素以(3)的方式彼此相互作用,并且整体的复杂性比线性增加更多。
软件的复杂性是(4)的属性,而不是偶然的。因此,消除其复杂性的软件实体的描述往往会抽象出其本质。数学和物理科学通过构建复杂现象的简化模型,从模型中导出属性,并通过实验验证这些属性,在三个世纪以来取得了长足的进步。这是因为模型中被忽略的复杂性(5)不是现象的基本属性。当复杂性是本质时,它不起作用。
开发软件产品的许多经典问题源于这一重要的复杂性,其非线性随着尺寸而增加。不仅技术问题,管理问题也来自于复杂性。
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