已知文法G[S]:S→A0|B1,A→S1|1,B→S0|0,该文法属于乔姆斯基定义的 (18) 文法,它不能产生串 (19) 。语言L=ambn|m≥0,n≥1)的正规表达式是 (20) 。一个文法G=(N,T,P,S),其中N是非终结符号的集合,T是终结符号的集合,P是产生式集合,S是开始符号,令集合V=N∪T,那么G所描述的语言是 (21) 的集合。程序设计语言引入“类”的概念是为了解决数据保护问题。C++语言将类的成员封装在类体之中,使之具有一定的存取规则,这些规则规定了存取类的成员的权利,其中对于用Private说明的成员,它 (22) 。 (22)处填()。
A. 既能被该类的成员函数访问,又能被外界直接访问
B. 只能被该类的成员函数访问,外界不能直接访问
C. 不能被该类的成员函数访问,只能被外界直接访问
D. 既不能被该类的成员函数访问,也不能被外界直接访问
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假设某程序语言的文法如下:S→SaT|TT→TbR|RT→PdR|P P→fSg|e其中:VT=a,b,d,e,f,g,VNS,T,R,P,S是开始符号。那么,此方法是 (38) 方法。这种文法的语法分析通常采用优先矩阵,优先矩阵给出了该文法中各个终结符之间的优先关系 (大于,小于,等于,无关系)。在上述文法中,某些终结符之间的优先关系如下:b (39) a:f (40) g;a (41) a;d (42) d。 (39)处填()。
A. 大于
B. 小于
C. 等于
D. 无关系
Passage ThreeQuestions 22 to 25 are based on the passage you have just heard.
A. His companion locked the speaker inside the cabin.
B. His companion jumped into the sea.
C. The speaker jumped into the sea.
D. His companion died in bed.
Questions 1 to 8 are based on the conversation you have just heard.
A. Opinions about the book are varied.
B. You shouldn’t believe everything you read.
C. The woman wonders which newspaper the man is reading.
D. The man thinks the book is excellent.
In information theory, "information" is regarded as knowledge which reduces or removes (71) about the occurrence of a specific event from a given set of possible events. The concept "event" is to be understood as used in the theory of probability. For instance, an event may be the occurrence of a (72) character or word in a given message or in a given position of a message.In communication theory, channel is defined as that part of a communication system that connects the message source with the message sink. An encoder may be inserted between the message source and the input to the channel, and a (73) between the output of the channel and the message sink. Generally, these two units are not considered as being parts of the channel. In certain cases, however, they may be considered as pans of the message source and message sink, (74) . In information theory (75) to Shannon, the channel can be characterized by the set of conditional probabilities of occurrence of all the messages received at the message sink when a given message emanates from the message source. (73)处填()。
A. debugger
B. decoder
C. decompiler
D. demodulator