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COBOL经典面试题库(1~64)
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COBOL经典面试题库(中英文版) 收藏
Q1) Name the divisions in a COBOL program ?.
A1) IDENTIFICATION DIVISION, ENVIRONMENT DIVISION, DATA DIVISION, PROCEDURE DIVISION.
Q:列举COBOL的DEVISION
A: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 numeric (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? - GS
A3) 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:88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 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0~9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) OCCURS 10 TIMES.
05 ARRAY2 PIC X(6) OCCURS 20 TIMES INDEXED BY WS-INDEX
Q: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? - GS
A10) Subscript refers to the array occurrence while index is the displacement (in no of bytes) from the beginning of the
array. An index can only be modified using PERFORM, SEARCH & SET. Need to have index for a table in order to
use 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? - GS
A11) SEARCH - is a serial search.
SEARCH ALL - is a binary search & the table must be sorted ( ASCENDING/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 ALL

Q12) What should be the sorting order for SEARCH ALL? - GS
A12) It can be either ASCENDING or DESCENDING. ASCENDING is default. If you want the search to be done on an
array sorted in descending order, then while defining the array, you should give DESCENDING KEY clause. (You
must 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.
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 the
11th item in this array, the program does not abend. What is wrong with it?
A14) 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NOSSRANGE

Q15) How do you sort in a COBOL program? Give sort file definition, sort statement syntax and meaning. - GS
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-2
GIVING 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 SECTION.
file-2 is the input file for the SORT and must be described using an FD entry in FILE SECTION and SELECT
clause in FILE CONTROL.
file-3 is the out file from the SORT and must be described using an FD entry in FILE SECTION and SELECT
clause in FILE CONTROL.
file-1, file-2 & file-3 should not be opened 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?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 data
being 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SORTWK01, 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? - GS
A17) 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 performed.
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? - GS
A18) Evaluate is like a case statement and can be used to replace nested Ifs. The difference between EVALUATE and
case is that no ‘break’ is required for EVALUATE i.e. control comes out of the EVALUATE as soon as one match is
made.
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-STATUS
WHEN A=B AND C=D WHEN 100 ALSO ‘00′
imperative stmt imperative stmt
WHEN (D+X)/Y = 4 WHEN -305 ALSO ‘32′
imperative stmt imperative stmt
WHEN OTHER WHEN OTHER
imperative stmt imperative stmt
END-EVALUATE END-EVALUATE

EVALUATE SQLCODE ALSO A=B EVALUATE SQLCODE ALSO TRUE
WHEN 100 ALSO TRUE WHEN 100 ALSO A=B
imperative stmt imperative stmt
WHEN -305 ALSO FALSE WHEN -305 ALSO (A/C=4)
imperative stmt imperative stmt
END-EVALUATE END-EVALUATE

Q20) How do you come out of an EVALUATE statement? - GS
A20) After the execution of one of the when clauses, the control is automatically passed on to the next sentence after the
EVALUATE statement. There is no need of any extra code.
Q:怎么跳出一条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 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? - GS
A23) PERFORM … …

END-PERFORM
Q:怎么使用内嵌的PERFORM
A: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 use
PERFORM Para name rather than in-line perform.
Q:什么时候使用内嵌式PERFORM
A: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 similar, that is, the control goes to the next sentence in the paragraph. But, Next Sentence would
take the control to the sentence after it finds a full stop (.). Check out by writing the following code example, one if
sentence followed by 3 display statements (sorry they appear one line here because of formatting restrictions) If 1 > 0
then next sentence end if display ‘line 1′ display ‘line 2′. display ‘line 3′. *** Note- there is a dot (.) only at the end of
the 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 SENTENCE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 > 0
THEN NEXT SENTENCE
END-IF
DISPLAY ‘LINE1′ DISPLAY ‘LINE2′. DISPLAY ‘LINE3′.(请注意代码中的‘.’号)
结果输出:LINE3
2:IF TEST-NUMERIC > 0
THEN CONTINUE
END-IF
DISPLAY ‘LINE1′ DISPLAY ‘LINE2′. DISPLAY ‘LINE3′.
结果输出:LINE1
LINE2
LINE3
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 PROGRAME

Q27) 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 while
DISPLAY 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 an X(200) field with a field of X(100) ?
Q31)1 Yes.
Q:能不能把X(200)的区域重定义成X(100)
A:可以,原因同上

Q31)2 What do you do to resolve SOC-7 error? - GS
Q31) Basically you need to correcting the offending data. Many times the reason for SOC7 is an un-initialized numeric item.
Examine that possibility first. Many installations provide you a dump for run time abend’s ( it can be generated also
by calling some subroutines or OS services thru assembly language). These dumps provide the offset of the last
instruction at which the abend occurred. Examine the compilation output XREF listing to get the verb and the line
number of the source code at this offset. Then you can look at the source code to find the bug. To get capture the
runtime dumps, you will have to define some datasets (SYSABOUT etc ) in the JCL. If none of these are helpful, use
judgement and DISPLAY to localize the source of error. Some installation might have batch program debugging
tools. Use them.
Q:怎么解决SOC-7错误
A:基本上你要看一下一些比较奇怪的数据,很多导致SOC7的原因都是因为数据项的初始化。
首先检查所有的可能性。某些功能可能提供一个空间用来存贮那些运行时间ABEND,并且提供最近一次运行时间ABEND的偏移量的说明(也就是位于队列中的位置),检查编译器的输出XREF队列以获得一些关键字。然后你就能看下源代码找出BUG。为了捕获一些运行时间的信息,你需要在JCL中建一个 DATASET(象SYSABOUT这样的),如果这些都没用,那么再审查一下ERROR出现的位置判断一下原因。有些软件安装了会提供批处理程序调试工具,那么可以就可以用这些工具了。
PS:以上大意就是说SOC-7这个错误多半是因为数据项初始化造成的,然后你应该到运行后编译器的返回信息中去找这些ERROR出现的地方(我们常用的话应该就是走查LOG),查的时候多注意下数据项的初始化问题。

Q32) How is sign stored in Packed Decimal fields and Zoned Decimal fields?
Q32) Packed Decimal fields: Sign is stored as a hex value in the last nibble (4 bits ) of the storage.
Zoned Decimal fields: As a default, sign is over punched with the numeric value stored in the last bite.
Q:在内部十进制区域和显示十进制区域符号是怎么存贮的
A:内部十进制是一个数字占4位(半字节),内存中用16进制来存,最后在追加4位作为符号,如-4=01001101(末尾的1101表示负,1100表示正),而我们用于显示的十进制,符号并不占空间,只是在最后一位上标识一下

Q33) How is sign stored in a comp-3 field? - GS
Q33) It is stored in the last nibble. For example if your number is +100, it stores hex 0C in the last byte, hex 1C if
your number is 101, hex 2C if your number is 102, hex 1D if the number is -101, hex 2D if the number is -102 etc…
Q:COMP-3区怎么存储符号
A:COMP-3采用的是内部十进制的存储方式,所谓内部十进制就是压缩式的外部十进制存储方式,上题讲过外部十进制每个数值都用1个字节存储,但前4位是存符号的,这样比较浪费存储空间,所以内部十进制的存储方式就用半个字节(4位)存储一个数字,在最后增加4位作为符号(1100(C)为正,1101(D)为负)

Q34) How is sign stored in a COMP field ? - GS
Q34) In the most significant bit. Bit is ON if -ve, OFF if +ve.
Q:COMP区怎么存储符号
A:COMP是采用定点二进制的方式存储数据,也就是将一个十进制的数值转化成二进制再进行存储,因为机器存储的形式也是二进制,所以定点二进制的读取是最快速的,因为COMP型的数据是用做计算(也就是说不用再转化成十进制打印),使用定点二进制将会非常高效。这样的存储方式符号是保存在最高有效果位上,如:10=(00001010)?,
-10=(00011010)?

Q35) What is the difference between COMP & COMP-3 ?
Q35) COMP is a binary storage format while COMP-3 is packed decimal format.
Q:COMP和COMP-3什么区别
A:这之前讲过了,COMP采用定点二进制存储,COMP-3采用内部十进制存储

Q36) What is COMP-1? COMP-2?
Q36) COMP-1 - Single precision floating point. Uses 4 bytes.
COMP-2 - Double precision floating point. Uses 8 bytes.
Q:COMP-1是什么?什么是COMP-2
A:其实之所以定义计算型数据(COMP~COMP-3)以区别DISPLAY(能计算,但是要用于打印)是为了考虑效率,因为大家知道文件导入(也就是 USER使用的数据)一般是十进制的,而机器存储都是二进制,那么当定义的数据光用来计算不用打印,处于效率考虑会把它定义成COMP型,当然就会衍生出几类COMP以适应不用的数据类型的存储。很明显,这里COMP-1就是采用内部短浮点(4个字节表示一个数,8位指数部分,24位表示数字部分),COMP-2用内部长浮点型(8个字节表示一个书,16位指数部分,48位表示数字部分)以适应浮点数据的存储,长浮点精确度更高.

Q37) How do you define a variable of COMP-1? COMP-2?
Q37) No picture clause to be given. Example 01 WS-VAR USAGE COMP-1.
Q:怎么定义一个COMP-1型?COMP-2型
A:不要用PICTURE描述,因为是确定分配多少内存的,直接用USAGE,如01 WS-VAR USAGE COMP-1

Q38) How many bytes does a S9(7) COMP-3 field occupy ?
Q38) Will take 4 bytes. Sign is stored as hex value in the last nibble. General formula is INT((n/2) + 1)), where n=7 in this
example.
Q:一个S9(7)的COMP-3型占用多少字节?
A:占用4字节。COMP-3用内部十进制存储,S9(7)中的S是要占空间的,符号占4位,7个数字,每个4位(半个字节),所以是(4+7*4)/8=4字节(字节和位的比例不要搞错了哦)

Q39) How many bytes does a S9(7) SIGN TRAILING SEPARATE field occupy ?
Q39) Will occupy 8 bytes (one extra byte for sign).
Q:一个S9(7) SIGN TRAILING SEPARATE区域占多少字节
A:这里是每个符号单独分配空间(也就是没个数值用1个字节表示,就象最常用的DISPLAY型的分配方式),算上S的空间,所以是7+1=8字节。一般情况省略的SIGN子句都是隐含SIGN IS TRAILING的

Q40) How many bytes will a S9(8) COMP field occupy ?
Q40) 4 bytes.
Q: 一个S9(8) COMP 区域占多少字节
A:如果之前关于COMP的解释听懂了的话,那很显然就是4字节了(定点二进制用2字节存储1~4,4字节存储5~9,……类推,你可以自己推下),如果这块还不懂的可以问我或者查下书

Q41) What is the maximum value that can be stored in S9(8) COMP?
Q41) 99999999
Q:S9(8)COMP型最多存储的最大值是什么
A:除了8个数值外不要忽略符号位

Q42) What is COMP SYNC?
Q42) Causes the item to be aligned on natural boundaries. Can be SYNCHRONIZED LEFT or RIGHT. For binary data
items, the address resolution is faster if they are located at word boundaries in the memory. For example, on main
frame the memory word size is 4 bytes. This means that each word will start from an address divisible by 4. If my
first variable is x(3) and next one is s9(4) comp, then if you do not specify the SYNC clause, S9(4) COMP will start
from byte 3 ( assuming that it starts from 0 ). If you specify SYNC, then the binary data item will start from address 4.
You might see some wastage of memory, but the access to this computational field is faster.
Q:COMP SYNC是什么
A:使数据项按“自然边界”排列。SYNCHRONIZED(简写SYNC)语句是同步安置语句。不同的机器会有一个机器字的概念(以一个WORD四个字节举例,这个数字因机器各异,但往往是四个字节),两个机器字之间就是这里说的“自然边界”,也就是说机器每次从内存中取出二个字节长度的数据,但是一个数据项中含有的数值可能跨越几个机器字或者未填满机器字,这样连续读取虽然比较省空间,但是要引用某些机器字的时候要把多个拿出来重新组织(因为一个数值可能跨越多个数据字,也可能未满,机器就要判断一个机器字中哪些是前一个数值哪些是下个数值)。如果向左对齐的话就是想左“自然边界”靠,也就是说未满一个数据字的用空格(对非数字项)或者零(数字项)填充,填充部分不能插入其他数据项的内容,同理向右对齐就是向机器字的右“自然边界”靠,类似的在左边的空余部分填充。按照自然边界存储相当与牺牲空间换取时间,存取效率,系统读取的机器字两段填充区域(0或者SPACE)之间就是一个数值,效率很高。

Q43) What is the maximum size of a 01 level item in COBOL I? in COBOL II?
Q43) In COBOL II: 16777215
Q:COBOL1定义的01层最大大小是多少,COBOL II中?
A:COBOL II中是16777215,没什么说的,自己翻书

Q44) How do you reference the following file formats from COBOL programs:
Q44)
Fixed Block File - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F,
BLOCK CONTAINS 0 .
Fixed Unblocked - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F,
do not use BLOCK CONTAINS
Variable Block File - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS V, BLOCK
CONTAINS 0. Do not code the 4 bytes for record length in FD ie JCL rec length will be max rec length in pgm + 4
Variable Unblocked - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS V, do not use
BLOCK CONTAINS. Do not code 4 bytes for record length in FD ie JCL rec length will
be max rec length in pgm + 4.
ESDS VSAM file - Use ORGANISATION IS SEQUENTIAL.
KSDS VSAM file - Use ORGANISATION IS INDEXED, RECORD KEY IS, ALTERNATE RECORD KEY IS RRDS File - Use ORGANISATION IS RELATIVE, RELATIVE KEY IS
Printer File - Use ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F, BLOCK
CONTAINS 0. (Use RECFM=FBA in JCL DCB).
Q:COBOL中如何涉及(引用调用)以下这些文件
A: 文件类型 这里是COBOL在文件控制区中的文件组织访问形式(SELECT下面那句)这里最好翻翻书或者事例代码反复记忆
定长文件 用 ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F, BLOCK CONTAINS 0
固定但是不是以块的组织形式 用 ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F, 不要使用BLOCK CONTAINS(因为不是以块的组织形式)
变长文件 用 ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS V,BLOCK ,CONTAINS 0.在之后的文件区中的文件描述FD中不要编码记录长度为4字节
变长但是不是以块的组织形式 用 ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS V,同样不要使用BLOCK CONTAINS也不要编码记录长度为4字节(原因同上)
ESDS VSAM文件 用ORGANISATION IS SEQUENTIAL
KSDS VSAM文件 用ORGANISATION IS INDEXED, RECORD KEY IS, ALTERNATE RECORD
作为关键字的RRDS文件 用ORGANISATION IS RELATIVE, RELATIVE KEY IS
打印文件 用ORGANISATION IS SEQUENTIAL. Use RECORDING MODE IS F, BLOCK CONTAINS 0. (Use RECFM=FBA in JCL DCB)
PS:这道题是阐述COBOL怎么调用外部的各种文件,在文件控制区以及文件区中要定义的一些关键字,有我们最熟悉的FB(定长)和VB(变长)(当然我们的前提是这两类都是以BLOCK(块)为单位的)但是也有不为我们所知的文件类型(可能出现的情况很少,但是也确实存在,比如编译出的MODULE放的 LOAD必须是V文件(文件组织形式是V))当然在不写ORGANISATION这些关键字的时候都是默认为FB的,但是在处理一些复杂数据(比如 VSAM数据)还有和外部文件(比如JCL)的连接的时候这些保留字都是要指定的,关于更具体的还是要翻书加强记忆

Q45) What are different file OPEN modes available in COBOL?
Q45) Open for INPUT, OUTPUT, I-O, EXTEND.
Q:COBOL中有哪些OPEN方式
A:有INPUT,OUTPUT,I-O,EXTEND这些OPEN模式

Q46) What is the mode in which you will OPEN a file for writing? - GS
Q46) OUTPUT, EXTEND
Q:当你想OPEN一个文件用来写入的时候,这属于什么方式
A:OUTPUT,EXTEND方式

Q47) In the JCL, how do you define the files referred to in a subroutine ?
Q47) Supply the DD cards just as you would for files referred to in the main program.
Q:JCL中怎么定义在子程序中要调用的文件
A:就象要在主程序中调用一样使用DD语句

Q48) Can you REWRITE a record in an ESDS file? Can you DELETE a record from it?
Q48) Can rewrite (record length must be same), but not delete.
Q:能否REWRITE(重写)一个ESDS文件?能否删除ESDS中的一条记录?
A:能够重写(但是记录长度必须相同),但是不能删除

Q49) What is file status 92? - GS
Q49) Logic error. e.g., a file is opened for input and an attempt is made to write to it.
Q:文件状态92是什么?
A:是文件状态的一个返回码,是逻辑错误的意思,比如,打开了一个文件用来导入数据但是又想将其他数据写入这个文件

Q50) What is file status 39 ?
Q50) Mismatch in LRECL or BLOCKSIZE or RECFM between your COBOL pgm & the JCL (or the dataset label). You
will get file status 39 on an OPEN.
Q:文件状态39是什么
A:当你的COBOL的逻辑记录长度(LRECL)或者块长度(BLOCKSIZE)或者记录形式(RECFM)和 JCL匹配错误,文件状态参数就会返回39

Q51) What is Static and Dynamic linking ?
Q51) In static linking, the called subroutine is link-edited into the calling program , while in dynamic linking, the subroutine & the main program will exist as separate load modules. You choose static/dynamic linking by choosing either the DYNAM or NODYNAM link edit option. (Even if you choose NODYNAM, a CALL identifier (as opposed to a CALL literal), will translate to a DYNAMIC call).A statically called subroutine will not be in its initial state the next time it is called unless you explicitly use INITIAL or you do a CANCEL. A dynamically called routine will always be in its initial state.
Q:什么是静态和动态连接
A:在静态连接中,被调用的子程序是连接到调用程序,但是在动态连接中,被调用子程序和调用主程序的可执行模块是都存在的(分开的)。你可以在连接选项中选择DYNAM或者NODYNAM(就算你选择了NODYNAM,CALL标识符还是回把它自动转换成一个动态调用)。静态子程序下次被调用时不会再处于其初始状态,除非用INITIAL初始化或者用CANCEL。动态的都是以初始状态存在的。

Q52) What is AMODE(24), AMODE(31), RMODE(24) and RMODE(ANY)? (applicable to only MVS/ESA
Enterprise Server).
Q52) These are compile/link edit options. Basically AMODE stands for Addressing mode and RMODE for Residency
mode.
AMODE(24) - 24 bit addressing;
AMODE(31) - 31 bit addressing
AMODE(ANY) - Either 24 bit or 31 bit addressing depending on RMODE.
RMODE(24) - Resides in virtual storage below 16 Meg line. Use this for 31 bit programs that call 24 bit programs.
(OS/VS Cobol pgms use 24 bit addresses only).
RMODE(ANY) - Can reside above or below 16 Meg line.
Q:AMODE(24),AMODE(31),RMODE(24)和RMODE(ANY)是什么?(仅适用于MVS/ESA 企业管理器)
A:是编译/连接的选项卡。基本上AMODE表示寻址方式,RMODE 表示贮存方式。
AMODE(24):24位的寻址方式
AMODE(31):31位的寻址方式
AMODE(ANY):是用24位还是31位的寻址方式取决于REMODE
RMODE(24):存在虚存中超过16Meg lne(MEG LINE是某种单位)允许31位的程序调用24位的程序。(OS/VS COBOL的PGM只有24位的存址)
RMODE(ANY)-超过或者不到16Meg line

Q53) What compiler option would you use for dynamic linking?
Q53) DYNAM.
Q:如果要动态连接那么要用什么编译选项
A:DYNAM

Q54) What is SSRANGE, NOSSRANGE ?
Q54) These are compiler options with respect to subscript out of range checking. NOSSRANGE is the default and if chosen,
no run time error will be flagged if your index or subscript goes out of the permissible range.
Q:SSRANGE,NOSSRANGE是什么
A:这在之前已经提到过了,是编译器的一个选项,用来核对数组索引或者下标的超界问题(比如只定义了10个元素程序却使用了第11个元素的情况)默认情况下是NOSSRANGE,如果选了NOSSRANGE,那么当索引和下标超界的时候也不会报RUN TIME ERROR

Q55) How do you set a return code to the JCL from a COBOL program?
Q55) Move a value to RETURN-CODE register. RETURN-CODE should not be declared in your program.
Q:怎么从一个COBOL程序设置一个JCL的返回码
A:把你想设置的值MOVE到RETURN-CODE这个寄存器中。RETURN-CODE寄存器并未在这COBOL程序中申明

Q56) How can you submit a job from COBOL programs?
Q56) Write JCL cards to a dataset with //xxxxxxx SYSOUT= (A,INTRDR) where ‘A’ is output class, and dataset should be
opened for output in the program. Define a 80 byte record layout for the file.
Q:怎么在COBOL程序中提交一个JOB
A:把一个JCL用“//xxxxxxx SYSOUT= (A,INTRDR)”写到一个DATASET中,A是输出组,在程序中要将这个DATASET作为OUTPUT(输出)打开。为这个文件定义一个80字节的记录格式长度

Q57) What are the differences between OS VS COBOL and VS COBOL II?
Q57) OS/VS Cobol pgms can only run in 24 bit addressing mode, VS Cobol II pgms can run either in 24 bit or 31 bit
addressing modes.
I. Report writer is supported only in OS/VS Cobol.
II. USAGE IS POINTER is supported only in VS COBOL II.
III. Reference modification e.g.: WS-VAR(1:2) is supported only in VS COBOL II.
IV. EVALUATE is supported only in VS COBOL II.
V. Scope terminators are supported only in VS COBOL II.
VI. OS/VS Cobol follows ANSI 74 stds while VS COBOL II follows ANSI 85 stds.
Under CICS Calls between VS COBOL II programs are supported.
Q:OS/VS COBOL和VS COBOL II有什么区别
A:OS/VS COBOL的PGM只能是24位地址的,VS COBOL II的PGM既能24位又能31位
报表writer只支持OS/VS COBOL
USAGE IS POINTER只支持VS COBOL II
REFERENCE(感觉翻成“引用”合适点)修改,比如:WS-VAR只支持VS COBOL II
只有COBOL II有EVALUATE语句
范围终止符只有COBOL II中才有
OS/VS COBOL是按照ANSI 74标准,VS COBOL II是按照ANSI 85标准
VS COBOL II程序之间允许CICS调用

Q58) What are the steps you go through while creating a COBOL program executable?
Q58) DB2 precompiler (if embedded SQL used), CICS translator (if CICS pgm), Cobol compiler, Link editor. If DB2
program, create plan by binding the DBRMs.
Q:建立一个COBOL可执行程序要通过哪些步骤
A:DB2预编译(如果内含SQL),CICS翻译器(如果是CICS PGM),COBOL编译器,连接编辑器,如果是DB2程序,要建立绑定DBRM的PLAN

Q59) Can you call an OS VS COBOL pgm from a VS COBOL II pgm ?
Q59) In non-CICS environment, it is possible. In CICS, this is not possible.
Q:能不能在VS COBOL II的PGM中调用OS VS COBOL的PGM?
A:在没有CICS的环境中,是可以的,在CICS环境中不行

Q60) What are the differences between COBOL and COBOL II?
A60) There are at least five differences:
COBOL II supports structured programming by using in line Performs and explicit scope terminators, It introduces
new features (EVALUATE, SET. TO TRUE, CALL. BY CONTEXT, etc) It permits programs to be loaded and
addressed above the 16-megabyte line It does not support many old features (READY TRACE, REPORT-WRITER,
ISAM, Etc.), and It offers enhanced CICS support.
Q:COBOL和COBOL II什么区别
A:有五点不同,COBOL II支持结构变成(通过PERFORMS和一系列范围终止符);COBOL II引进了些新的特性(如EVALUATE,SET TO TRUE,CALL,BY CONTEXT,等等),COBOL II允许程序编址在16MB行上;COBOL II不支持一些旧的特性(如READY TRACE,REPORT-WRITER,ISAM,ETC),以及支持加强版CICS

Q61) What is an explicit scope terminator?
A61) A scope terminator brackets its preceding verb, e.g. IF .. END-IF, so that all statements between the verb and its scope terminator are grouped together. Other common COBOL II verbs are READ, PERFORM, EVALUATE, SEARCH and STRING.
Q:什么是范围终止符
A:一个范围终止符和其之前的动词配套使用,如,IF和END-IF,以至于前置动词和终止符一起作用。COBOL II其他普通的词是READ,PERFORM,EVALUATE,SEARCH和STRING

Q62) What is an in line PERFORM? When would you use it? Anything else to say about it?
A62) The PERFORM and END-PERFORM statements bracket all COBOL II statements between them. The COBOL equivalent is to PERFORM or PERFORM THRU a paragraph. In line PERFORMs work as long as there are no internal GO TOs, not even to an exit. The in line PERFORM for readability should not exceed a page length - often it will reference other PERFORM paragraphs.
Q:PERFORM行有什么作用?什么时候使用?简单介绍下它
A:PERFORM和END-PERFORM配套使用,所有COBOL II程序语句都在这两关键字之间。这和COBOL的PERFORM或者PERFORM THRU一段是一样的意思。在PERFORM的语句中只要没有内部GOTO就一直执行直到碰到EXIT。在行PERFORM语句中为了可读型不能超过一页的长度,他经常会引用到其他PERFORM段

Q63) What is the difference between NEXT SENTENCE and CONTINUE?
A63) NEXT SENTENCE gives control to the verb following the next period. CONTINUE gives control to the next verb after the explicit scope terminator. (This is not one of COBOL II’s finer implementations). It’s safest to use CONTINUE rather than NEXT SENTENCE in COBOL II.
Q:NEXT SENTENCE和CONTINUE有什么区别
A:(这在前面已经详细说明,这样仅就文字翻译)NEXT SENTENCE当碰到‘.’转移程序控制权给下句,CONTINUE碰到范围终止符就转移程序控制权给下句。所以用CONTINUE比用NEXT SENTENCE安全(即使忘记写‘.’也没有关系)。

Q64) What COBOL construct is the COBOL II EVALUATE meant to replace?
A64) EVALUATE can be used in place of the nested IF THEN ELSE statements.
Q:COBOL II中的EVALUATE相当于取代了COBOL中的什么结构
A:EVALUATE相当于取代了COBOL中的IF THEN ELSE的嵌套语句

[COBOL经典面试题库(1~64)]的回复

buangirl 于 2010-07-06 23:50:51 发表 | IP:210.30.98.*
40题,S9(8)不应该是定义了8个数字,所以应该是8*4个bytes吗
柠檬园主 2010-07-07 03:36:18 回复:

 注意,那题说的是S9(8) COMP类型,即是压缩型数字.

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