全国计算机等级考试四级模拟试题四.docx

1、全国计算机等级考试四级模拟试题四2019年全国计算机等级考试四级模拟试题(四)(67) How many key comparisons occur in searching for key 35 in the given hash table? (2分) A) 0 B) 1 C) 2 D) 3 (68)& If a new key 67 is inserted into the given hash table, what will be its address? (2分) A) 3 B) 4 C) 5 D) 6 (69) Suppose the contents of the DOS IF

2、1.BAT file on the hard disk is as follows. ECHO OFF MEMFILE1 SORTFILE2 DEL FILE1 DATE TIME IF EXIST %1 ECHO % IF FOUND If all of the commands are successfully executed after IF1 FILE1 is typed, then the screen displays? A) None B) Date and time C) FILE1 IS FOUND D) FILE2 IS FOUND (70) If the files i

3、n the current directory are aac, abc, acb,acc, aca, ao, al, a2, ab, ac, aa, and the command ls a?bc is executed, how many files will be listed? (2分) A) 3 B) 4 C) 5 D) 6 (71) In order to append a standard output to an existing file, which of the following operators is used in the UNIX system? A) | B)

4、 & C) D) (72) Consider the following figure, where the shaded parts represent already assigned blocks of memory, and the unshaded parts represent free blocks. (2分) If there is a request for 40KB of memory and the best-fit algorithm is used, then the beginning address of memory that is allocated in r

5、esponse to the request is A) 100KB B) 190KB C) 330KB D) 410KB (73) On a certain disk, there are 200 tracks, numbered 0-199, the current position of the disk head is track 53. If the shortest-seek-time-first scheduling algorithm is used when the tracks 98, 183, 37, 122, 14, 124, 65, 67 are requested,

6、 then the head-moving sequence that results will be (2分) A) 65, 67, 37, 14, 98, 122, 124, 183 B) 65, 67, 37, 98, 122, 124, 183, 14 C) 65, 67, 98, 122, 124, 183, 37, 14 D) 98, 183, 37, 122, 14, 124, 65, 67 (74) Whant operation on relations R and S produces the relation shown below? tupletupleRtuple S

7、 A) Union B) Difference C) Intersection D) Division (75) When embedding SQL in a C language program, the prefix that should be added to all SQL statements in order to distinguish SQL statements from the host language statements is A) ： B) EXEC C) EXEC SQL D) SQL (76) In the ORACLE system,sets of SQL

8、 statements and control flow statements that have been named,compiled,and stored tn the database are referred to as stored A) batches B) procedures C) triggers D) transactions (77) Which of the following statements about object oriented databases is NOT correct? (2分) A) Each object has a unique obje

9、ct identity in the system. B) Encapsulation and inheritance are two important features of object oriented databases. C) A subclass can inherit the attributes and methods of all its superclasses. D) A superclass includes the attributes and methods of all its subclasses. (78) In the design phase of so

10、ftware engineering, decomposition of the program into modules should follow the principles of A) low cohesion with low corpling B) low cohesion with high coupling C) high cohesion with low coupling D) high cohesion with high coupling (79) Specifications for software should contain&nbs p;several comp

11、onents, e.g., specifications of information flow, user interface, functional requirements, and design constraints. Two other important components are specifications of the (2分) A) methods of testing and ways to obtain quality assurance B) criteria for testing and ways to obtain quality assurance C)

12、methods of testing and criteria for function assurane D) criteria for testing and methods of function assurance(80) Which of the following statements about testing software with data is (are) true? I. The primary purpose of such testing is to find errors. II. Such testing can demonstrate the existen

13、ce of errors but cannot demonstrate the absence of errors. A) Neither B) only C) only D) and (81) The type of testing done during software implementation and beforemodule integration is called A) unit testing B) beta testing C) system testing D) acceptance testing (82) Which of the following is (are

14、) true about software portability? I. Using a high-level language that conforms to an ISO standardguarantees portability across the range of machines that support the language. II. Portability is guaranteed across all machines that have the same instruction set and operating system. (2分) A) Neither

15、B) only C) only D) and (83) A memory-memory, machine instruction for a certain machine has the following format. (Such an instruction is similar to a register-register instruction except that the operands are displaced addresses in memory.) opcode meml displ1 mem2 displ2 Which of the following could

16、 be an assembly lanuage instruction that would be translated into a memory-to-memory instruction for this machine? A) ADD 10(R1), 20(R2) B) ADD(10R1), (20R2) C) ADD R1, 10(R2), 20 D) ADD R1, 10, 20(R2) (84) In a certain cache system, the modified cache block is written to main memory only when the b

17、lock is replaced. All of the following are used to describe this policy EXCEPT A) store-in B) write-back C) copy-back D) write-through (85) When an amount of memory is requested that is less than the size of a page, but a full page is allocated, the r esulting waste of memory is called A) external f

18、ragmentation B) internal fragmentation C) inaccessible page faults D) inaccessible garbage (86) The time that the CPU spends on a given program can be computed using all of the following expressions EXCEPT (2分) A) (CPU clock cycles for the program)*(clock cycle time) B) CPU clock cycles for the prog

19、ram clock rate C) (Instruction count)*CPI clock rate D) (CPU clock cycles for the program)*CPI clock rate (87) The methods used in Asynchronous Transfer Mode (ATM) are switch technology and which of the following is used to describe this mode? A) cell exchange B) packet exchange C) message exchange

20、D) information exchange (88) In a data communication system, the transport media with the widest frequency band and best reliability is the A) telephone line B) coaxial cable C) radio channel D) fiber optic cable (89) Which of the following statements about the Internet is (are) true? I. It is possi

21、ble to have multiple names corresponding to the same IP address. II. All host names must be registered with an Internet-wide central registry. A) Neither B) only C) only D) and (90) According to the principle of CRC calculation, given a frame-bit series M =11100111 and the multiple-term formula, frame-bit series generated by the CRC G =110011, then the CRC is (2分) A) 111101 B) 00011 C) 11010011 D) 1101001