先学习基础概念
1、COBOL字符:包含:
- User-defined words 用户定义字符
- System-names
- Reserved words 关键字
2、用户定义字符User-defined words:合法的定义:
- A - Z
- a - z
- 0 - 9
- - (连字符).
3、系统名 System-names
- Computer-names
- Language-names
- Implementor-names:
- Environment-name
- Assignment-name
4、关键词 Reserved words
ACCEPTACCESSACQUIRE ADDADDRESS ADVANCINGAFTERALLALPHABETALPHABETICALPHABETIC-LOWERALPHABETIC-UPPERALPHANUMERICALPHANUMERIC-EDITEDALSOALTERALTERNATEANDANY AREAREAAREASARITHMETIC ASCENDINGASSIGNATAUTHORAUTO AUTO-SKIP BACKGROUND-COLOR BACKGROUND-COLOUR B-AND BEEP BEFOREBELL B-EXOR BINARYBIT BITS BLANKB-LESS BLINK BLOCKB-NOT BOOLEAN B-OR BOTTOMBYCALLCANCELCD CF CH CHARACTERCHARACTERSCLASSCLOCK-UNITS CLOSECOBOL CODE CODE-SETCOL COLLATINGCOLUMN COMMACOMMIT COMMITMENT COMMON COMMUNICATION COMPCOMP-3COMP-4COMPUTATIONALCOMPUTATIONAL-3COMPUTATIONAL-4COMPUTECONFIGURATIONCONNECT CONTAINED CONTAINSCONTENTCONTINUECONTROLCONTROL-AREA CONTROLSCONVERSION CONVERTINGCOPYCORRCORRESPONDINGCOUNTCRT CRT-UNDER CURRENCYCURRENT CURSOR DATADATEDATE-COMPILEDDATE-WRITTENDAYDAY-OF-WEEK DB DB-ACCESS-CONTROL-KEY DB-DATA-NAME DB-EXCEPTION DB-FORMAT-NAME DB-RECORD-NAME DB-SET-NAME DB-STATUS DBCS DE DEBUG-CONTENTSDEBUG-ITEMDEBUG-LINEDEBUG-NAMEDEBUG-SUB-1DEBUG-SUB-2DEBUG-SUB-3DEBUGGINGDECIMAL-POINTDECLARATIVESDEFAULT DELETEDELIMITEDDELIMITERDEPENDINGDESCENDINGDESTINATION DETAIL DISABLE DISCONNECT DISPLAYDISPLAY-1 DISPLAY-n DIVIDEDIVISIONDOWNDROP DUPLICATE DUPLICATESDYNAMICEGI EJECT ELSEEMI EMPTY-CHECK ENABLE ENDEND-ACCEPT END-ADDEND-CALLEND-COMPUTEEND-DELETEEND-DIVIDEEND-EVALUATEEND-IFEND-MULTIPLYEND-OF-PAGEEND-PERFORMEND-READEND-RECEIVE END-RETURNEND-REWRITEEND-SEARCHEND-STARTEND-STRINGEND-SUBTRACTEND-UNSTRINGEND-WRITEENTERENVIRONMENTEOPEQUALEQUALS ERASE ERRORESI EVALUATEEVERYEXCEEDS EXCEPTIONEXCLUSIVE EXITEXOR EXTENDEXTERNAL EXTERNALLY-DESCRIBED-KEY FALSE FDFETCH FILEFILE-CONTROLFILES FILLERFINAL FIND FINISH FIRSTFOOTINGFORFOREGROUND-COLOR FOREGROUND-COLOUR FORMAT FREE FROMFULL FUNCTION GENERATEGET GIVINGGLOBAL GOGOBACK GREATERGROUP HEADING HIGHLIGHT HIGH-VALUEHIGH-VALUESI-OI-O-CONTROLID IDENTIFICATIONIFININDEXINDEXEDINDEX-N INDIC INDICATEINDICATOR INDICATORS INITIALINITIALIZEINITIATEINPUTINPUT-OUTPUTINSPECTINSTALLATIONINTOINVALIDISJUSTJUSTIFIEDKEEP KEYLABELLASTLD LEADINGLEFTLEFT-JUSTIFY LENGTHLENGTH-CHECK LESSLIKE LIMIT LIMITS LINAGELINAGE-COUNTERLINELINE-COUNTER LINESLINKAGELOCALLY LOCKLOW-VALUELOW-VALUESMEMBER MEMORYMERGEMESSAGE MODEMODIFIED MODIFY MODULESMOVEMULTIPLEMULTIPLYNATIVENEGATIVENEXTNONO-ECHO NONE NOTNULL NULLS NUMBER NUMERICNUMERIC-EDITEDOBJECT-COMPUTEROCCURSOFOFFOMITTEDONONLY OPENOPTIONALORORDERORGANIZATIONOTHER OUTPUTOVERFLOWOWNER PACKED-DECIMALPADDING PAGEPAGE-COUNTER PERFORMPF PH PICPICTUREPLUS POINTERPOSITIONPOSITIVEPRESENT PRINTINGPRIOR PROCEDUREPROCEDURESPROCEEDPROCESS PROGRAMPROGRAM-IDPROMPT PROTECTED PURGE QUEUE QUOTEQUOTESRANDOMRD READREADY REALM RECEIVE RECONNECT RECORDRECORD-NAME RECORDSREDEFINESREELREFERENCEREFERENCE-MONITOR REFERENCESRELATION RELATIVERELEASEREMAINDERREMOVALRENAMESREPEATED REPLACE REPLACINGREPORT REPORTING REPORTS REQUIRED RERUNRESERVERESET RETAINING RETRIEVAL RETURNRETURN-CODE REVERSEDREVERSE-VIDEO REWINDREWRITERD RF RH RIGHTRIGHT-JUSTIFY ROLLBACK ROLLING ROUNDEDRUNSAMESCREEN SDSEARCHSECTIONSECURE SECURITYSEGMENT SEGMENT-LIMITSELECTSEND SENTENCESEPARATESEQUENCESEQUENTIALSETSHARED SIGNSIZESKIP1 SKIP2 SKIP3 SORTSORT-MERGESORT-RETURN SOURCE SOURCE-COMPUTERSPACESPACE-FILL SPACESSPECIAL-NAMESSTANDARDSTANDARD-1STANDARD-2STARTSTARTING STATUSSTOPSTORE STRINGSUB-QUEUE-1 SUB-QUEUE-2 SUB-QUEUE-3 SUB-SCHEMA SUBFILE SUBTRACTSUM SUPPRESSSYMBOLIC SYNCSYNCHRONIZEDTABLE TALLYINGTAPETENANT TERMINALTERMINATE TESTTEXT THANTHENTHROUGHTHRUTIMETIMESTITLE TOTOPTRAILINGTRAILING-SIGN TRANSACTION TRUETYPE UNDERLINE UNEQUAL UNITUNSTRINGUNTILUPUPDATE UPONUSAGEUSAGE-MODE USEUSINGVALID VALIDATE VALUEVALUESVARYINGWAIT WHENWHEN-COMPILED WITHWITHIN WORDSWORKING-STORAGEWRITEZEROZEROESZERO-FILL ZEROS<< =+***-/>> ==
近500个关键字.
5、节和段 Sections and Paragraphs
层次:
Identification Division
Paragraphs Entries Clauses Environment Division Sections Paragraphs Entries Clauses Phrases Data Division Sections Entries Clauses Phrases Procedure Division Sections Paragraphs Sentences Statements Phrases备注:
4个部:
- 1、标识部(IDENTIFICATIONDIVISION):用于标识程序名。
- 2、环境部(ENVIRONMENTDIVISION):用于说明程序运行的环境。
- 3、数据部(DATADIVISION):用于说明程序中涉及的所有数据。
- 4、过程部(PROCEDUREDIVISION):是程序的核心部分,它决定计算机应进行什么操作。
6、Cobol 代码格式
第1至6列为”标号区”
序列号是可选的。 如果使用的话,序列号必须 在列1到6
第7列为”续行标志区” 第8至此11列,称为”A区”。程序中有些内容如部头,节头,段头,层号01,层号77及文件描述符FD等应从A区开始写。 第12至此72列,称为”B区”。写程序中的正文部分。如过程部中的句子只能从B区开始写。 第73至80列,称为”注释区”。
格式演示: