COBOL经典面试题库中英文版.docx

1、COBOL经典面试题库中英文版COBOL经典面试题库（中英文版）Q1) Name the divisions in a COBOL program ?.A1) IDENTIFICATION DIVISION, ENVIRONMENT DIVISION, DATA DIVISION, PROCEDURE DIVISION.Q：列举COBOL的DEVISIONA：标识部，环境部，数据部，过程部Q2) What are the different data types available in COBOL?A2) Alpha-numeric (X), alphabetic (A) and numer

2、ic (9).Q：COBOL有哪些可用的数据类型A：字符型（这里指的是包含字母和数字），字母型，数字型Q3) What does the INITIALIZE verb do? - GSA3) Alphabetic, Alphanumeric fields & alphanumeric edited items are set to SPACES. Numeric, Numeric edited items set to ZERO. FILLER , OCCURS DEPENDING ON items left untouched.Q：INITIALIZE这个词做了些什么A：将字母，字符，数字

3、区域都置成空格（置空），将数字区置0， FILLER和OCCURS DEPENDING ON项不处理Q4) What is 77 level used for ?A4) Elementary level item. Cannot be subdivisions of other items (cannot be qualified), nor can they be subdivided themselves.Q：77层有什么作用A：基本层数据项，不能用做细分别的层，也不能被细分Q5) What is 88 level used for ?A5) For condition names.Q：8

4、8层有什么作用A：条件逻辑层Q6) What is level 66 used for ?A6) For RENAMES clause.Q：66层有什么作用A：重命名层Q7) What does the IS NUMERIC clause establish ?A7) IS NUMERIC can be used on alphanumeric items, signed numeric & packed decimal items and unsigned numeric & packed decimal items. IS NUMERIC returns TRUE if the item

5、only consists of 0-9. However, if the item being tested is a signed item, then it may contain 0-9, + and - .Q：IS NUMERIC这个子句怎么确定（也就是说确定句子的真值）A：IS NUMERIC用在字符项，带符号数字，浮点数，不带符号数。如果目标项只含09则返回TRUE。但是，如果待测项目是个带符号数，那么他就含有0-9还有+和-Q8) How do you define a table/array in COBOL?A8) ARRAYS.05 ARRAY1 PIC X(9) OCC

6、URS 10 TIMES.05 ARRAY2 PIC X(6) OCCURS 20 TIMES INDEXED BY WS-INDEXQ：COBOL中怎么建表/数组A：如上.Q9) Can the OCCURS clause be at the 01 level?A9) No.Q：OCCURS 子句能用在第一层吗A：不能Q10) What is the difference between index and subscript? - GSA10) Subscript refers to the array occurrence while index is the displacement

7、(in no of bytes) from the beginning of thearray. An index can only be modified using PERFORM, SEARCH & SET. Need to have index for a table in order touse SEARCH, SEARCH ALL.Q：索引和下标有什么区别A：下标可以指定数组中任意中位置的元素（只要知道其下标），下标只能是数字型常量或者数字型变量（但是不能在指定的时候修改，如：A（K+1）这样是不行的，要修改的话要在指定的外部改，如：ADD 1 TO K，而索引的话是从表头/数组头

8、开始检索（以BY N的指定检索规律往后滚）再者，索引只能通过PERFORM, SEARCH 和SET来修改，如果要在一个表中使用SEARCH, SEARCH ALL，那这个表就要有索引（因为SEARCH, SEARCH ALL的参数中指定索引，所以即使其有很多限制还是得用它）Q11) What is the difference between SEARCH and SEARCH ALL? - GSA11) SEARCH - is a serial search.SEARCH ALL - is a binary search & the table must be sorted ( ASCEN

9、DING/DESCENDING KEY clause to be used & data loaded in this order) before using SEARCH ALL.Q：SERACH和SERACH ALL有什么区别A：SEARCH是顺序查找SERACH ALL 是2叉查找（相信数据结构学过2叉树的都不会陌生），在使用SEARCH ALL前表必须有一个递增/递减的KEY，并且表已经按照其KEY值排序了，这样才能使用SEARCH ALLQ12) What should be the sorting order for SEARCH ALL? - GSA12) It can be e

10、ither ASCENDING or DESCENDING. ASCENDING is default. If you want the search to be done on anarray sorted in descending order, then while defining the array, you should give DESCENDING KEY clause. (Youmust load the table in the specified order).Q：为了使用SEARCH ALL，存贮顺序是怎么样的A：他必须是递增或者是递减的，默认地政。如果你想在一个递减顺

11、序存贮的表/数组使用搜索的话，那么当定义表/数组的时候你应该加一个DESCENDING KEY子句（这之前表要已经按指定的顺序排序了）Q13) What is binary search?A13) Search on a sorted array. Compare the item to be searched with the item at the center. If it matches, fine else repeat the process with the left half or the right half depending on where the item lies.

12、Q：什么是2叉查找A：将你要找的目标项与数组的正中项比较，找到就结束搜索，没找到则继续如此循环（比较下一个中值），取哪一半取决于目标值大于中值还是小于中值PS：联想2叉树的查找规律就很好理解，因为所谓的“表“本身也就是数组Q14) My program has an array defined to have 10 items. Due to a bug, I find that even if the program access the11th item in this array, the program does not abend. What is wrong with it?A14

13、) Must use compiler option SSRANGE if you want array bounds checking. Default is NOSSRANGE.Q：我的程序有个数组定义了10项。因为有个BUG，我发现即使访问第11项，程序也不异常终止。那是出了什么问题A：必须使用编译器的一个选项SSRANGE，如果你想检查数组的超界问题。默认是NOSSRANGEQ15) How do you sort in a COBOL program? Give sort file definition, sort statement syntax and meaning. - GS

14、A15) Syntax: SORT file-1 ON ASCENDING/DESCENDING KEY key. USING file-2 GIVING file-3.USING can be substituted by INPUT PROCEDURE IS para-1 THRU para-2GIVING can be substituted by OUTPUT PROCEDURE IS para-1 THRU para-2.file-1 is the sort (work) file and must be described using SD entry in FILE SECTIO

15、N.file-2 is the input file for the SORT and must be described using an FD entry in FILE SECTION and SELECTclause in FILE CONTROL.file-3 is the out file from the SORT and must be described using an FD entry in FILE SECTION and SELECTclause in FILE CONTROL.file-1, file-2 & file-3 should not be opened

16、explicitly.INPUT PROCEDURE is executed before the sort and records must be RELEASEd to the sort work file from the input procedure.OUTPUT PROCEDURE is executed after all records have been sorted. Records from the sort work file must be RETURNed one at a time to the output procedure.Q：怎么在一个COBOL程序中排序

17、？给出排序文件的定义，排序语法和意思A：语法就是SORT file-1 ON ASCENDING/DESCENDING KEY key. USING file-2 GIVING file-3.USING后程序的输入接口，这个地方可以替换成一个输出过程，也就是说写一个过程往USING这个接口中导数据（要在这个过程中READ，AT END，），这个过程在将数据释放到执行排序的文件中之前执行，GIVING后是输出借口，用法类似。此例中输入文件是file-2输出文件是file3(这样个文件必须在文件区中用FD和在文件控制中用到SELECT)真正执行排序的file-1，这里需要注意的是file-1中的文

18、件区不能用FD，应该用SD，file-2和3还是一样（用FD），具体可以看一下书上的例子Q16) How do you define a sort file in JCL that runs the COBOL program?A16) Use the SORTWK01, SORTWK02,. dd names in the step. Number of sort datasets depends on the volume of databeing sorted, but a minimum of 3 is required.Q：怎么在JCL中定义一个排序文件来跑这个COBOL程序A：用S

19、ORTWK01, SORTWK02,.作为DATA SET NAME。用多少取决于你要排序的数量，但是至少3个。Q17) What is the difference between performing a SECTION and a PARAGRAPH? - GSA17) Performing a SECTION will cause all the paragraphs that are part of the section, to be performed.Performing a PARAGRAPH will cause only that paragraph to be perf

20、ormed.Q：执行一个区和一个段有什么区别A：简单来说的话就是区的概念比段大，执行一个区就要执行其内部所有段，执行段的话只执行该段。Q18) What is the use of EVALUATE statement? - GSA18) Evaluate is like a case statement and can be used to replace nested Ifs. The difference between EVALUATE andcase is that no break is required for EVALUATE i.e. control comes out of

21、 the EVALUATE as soon as one match ismade.Q：EVALUATE语句有什么作用A：EVALUATE就象个CASE语句（多重开关语句，学过C的总知道吧），不同点在于EVALUATE不需要BREAK，一旦匹配就跳出EVALUATE语句了Q19) What are the different forms of EVALUATE statement?A19)EVALUATE EVALUATE SQLCODE ALSO FILE-STATUSWHEN A=B AND C=D WHEN 100 ALSO 00imperative stmt imperative st

22、mtWHEN (D+X)/Y = 4 WHEN -305 ALSO 32imperative stmt imperative stmtWHEN OTHER WHEN OTHERimperative stmt imperative stmtEND-EVALUATE END-EVALUATEEVALUATE SQLCODE ALSO A=B EVALUATE SQLCODE ALSO TRUEWHEN 100 ALSO TRUE WHEN 100 ALSO A=Bimperative stmt imperative stmtWHEN -305 ALSO FALSE WHEN -305 ALSO (

23、A/C=4)imperative stmt imperative stmtEND-EVALUATE END-EVALUATEQ20) How do you come out of an EVALUATE statement? - GSA20) After the execution of one of the when clauses, the control is automatically passed on to the next sentence after theEVALUATE statement. There is no need of any extra code.Q：怎么跳出

24、一条EVALUATE语句A：象18题目说的那样，一旦匹配了某一个“WHEN“语句就自动跳出了，不需要什么额外的代码来跳出Q21) In an EVALUATE statement, can I give a complex condition on a when clause?A21) Yes.Q：在一个EVALUATE语句的某个WHEN分支中能否再插入复杂的情况（也就是嵌套）A：当然可以，当多个参数作为控制变量的时候1个WHEN内部可以嵌套更多的情况Q22) What is a scope terminator? Give examples.A22) Scope terminator is

25、used to mark the end of a verb e.g. EVALUATE, END-EVALUATE; IF, END-IF.Q：什么是结束终止符A：结束终止符是搭配一些范围指令的，也就是标识一些范围指令的结束。如：EVALUATE, END-EVALUATE; IF, END-IF 如果没有该结束符，该条语句将终止不了Q23) How do you do in-line PERFORM? - GSA23) PERFORM END-PERFORMQ：怎么使用内嵌的PERFORMA：PERFORM END-PERFORM所谓内嵌也就是PERFORM被嵌在某些比如循环语句中担当执行

26、主体，同时通过UNTIL来指定结束判定Q24) When would you use in-line perform?A24) When the body of the perform will not be used in other paragraphs. If the body of the perform is a generic type of code(used from various other places in the program), it would be better to put the code in a separate Para and usePERFORM

27、 Para name rather than in-line perform.Q：什么时候使用内嵌式PERFORMA：当该段PERFORM的内容不被其他段用到，只在某些局部代码中（当然PERFORM的主体所用到的参数也都是局部的，例如循环）使用，如果 PERFORM主体的代码是一般的（用到了别的程序段的变量），还是使用PERFORM Para name这样的形式比较好（也就是相对与内于PERFORM的外部PERFORM）。Q25) What is the difference between CONTINUE & NEXT SENTENCE ?A25) They appear to be si

28、milar, that is, the control goes to the next sentence in the paragraph. But, Next Sentence wouldtake the control to the sentence after it finds a full stop (.). Check out by writing the following code example, one ifsentence followed by 3 display statements (sorry they appear one line here because o

29、f formatting restrictions) If 1 0then next sentence end if display line 1 display line 2. display line 3. * Note- there is a dot (.) only at the end ofthe last 2 statements, see the effect by replacing Next Sentence with Continue *Q：CONTINUE 和 NEXT SENTENCE有什么不同A：两者比较相似，都是将程序控制权交给下一句，但是用NEXT SENTENC

30、E的时候，只有当碰到句结束符（就是句末的.）才会将执行下句这道题我用了2个例子测试了一下：1：IF TEST-NUMERIC 0THEN NEXT SENTENCEEND-IFDISPLAY LINE1 DISPLAY LINE2. DISPLAY LINE3.（请注意代码中的.号）结果输出：LINE32：IF TEST-NUMERIC 0THEN CONTINUEEND-IFDISPLAY LINE1 DISPLAY LINE2. DISPLAY LINE3.结果输出：LINE1LINE2LINE3相信已经区别已经比较明显了，NEXT SENTENCE是靠句末的结束符（也就是.）来判断下一句

31、的，而CONTINUE是通过句头的保留字（这例中是DISPLAY）来判断下一句的Q26) What does EXIT do ?A26) Does nothing ! If used, must be the only sentence within a paragraph.Q：EXIT语句有什么作用A：什么都不做，如果用到的话，肯定是作为一段的唯一的一句话，注意：这里不是子程序中用的EXIT PROGRAMEQ27) Can I redefine an X(100) field with a field of X(200)?A27) Yes. Redefines just causes both fields to start at the same location. For example:01 WS-TOP PIC X(1)01 WS-TOP-RED REDEFINES WS-TOP PIC X(2).If you MOVE 12 to WS-TOP-RED,DISPLAY WS-TOP will show 1 whileDISPLAY WS-TOP-RED will show 12.Q：能不能把X（100）的区域重定义成X（200）A：可以，重定义只是相当于把两个区域的首地址放在一起，从上面这个例子也很好理解A28) Can I redefine