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
ACCEPT ACCESS ACQUIRE ADD ADDRESS ADVANCING AFTER ALL ALPHABET ALPHABETIC ALPHABETIC-LOWER ALPHABETIC-UPPER ALPHANUMERIC ALPHANUMERIC-EDITED ALSO ALTER ALTERNATE AND ANY ARE AREA AREAS ARITHMETIC ASCENDING ASSIGN AT AUTHOR AUTO AUTO-SKIP BACKGROUND-COLOR BACKGROUND-COLOUR B-AND BEEP BEFORE BELL B-EXOR BINARY BIT BITS BLANK B-LESS BLINK BLOCK B-NOT BOOLEAN B-OR BOTTOM BY CALL CANCEL CD CF CH CHARACTER CHARACTERS CLASS CLOCK-UNITS CLOSE COBOL CODE CODE-SET COL COLLATING COLUMN COMMA COMMIT COMMITMENT COMMON COMMUNICATION COMP COMP-3 COMP-4 COMPUTATIONAL COMPUTATIONAL-3 COMPUTATIONAL-4 COMPUTE CONFIGURATION CONNECT CONTAINED CONTAINS CONTENT CONTINUE CONTROL CONTROL-AREA CONTROLS CONVERSION CONVERTING COPY CORR CORRESPONDING COUNT CRT CRT-UNDER CURRENCY CURRENT CURSOR DATA DATE DATE-COMPILED DATE-WRITTEN DAY DAY-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-CONTENTS DEBUG-ITEM DEBUG-LINE DEBUG-NAME DEBUG-SUB-1 DEBUG-SUB-2 DEBUG-SUB-3 DEBUGGING DECIMAL-POINT DECLARATIVES DEFAULT DELETE DELIMITED DELIMITER DEPENDING DESCENDING DESTINATION DETAIL DISABLE DISCONNECT DISPLAY DISPLAY-1 DISPLAY-n DIVIDE DIVISION DOWN DROP DUPLICATE DUPLICATES DYNAMIC EGI EJECT ELSE EMI EMPTY-CHECK ENABLE END END-ACCEPT END-ADD END-CALL END-COMPUTE END-DELETE END-DIVIDE END-EVALUATE END-IF END-MULTIPLY END-OF-PAGE END-PERFORM END-READ END-RECEIVE END-RETURN END-REWRITE END-SEARCH END-START END-STRING END-SUBTRACT END-UNSTRING END-WRITE ENTER ENVIRONMENT EOP EQUAL EQUALS ERASE ERROR ESI EVALUATE EVERY EXCEEDS EXCEPTION EXCLUSIVE EXIT EXOR EXTEND EXTERNAL EXTERNALLY-DESCRIBED-KEY FALSE FD FETCH FILE FILE-CONTROL FILES FILLER FINAL FIND FINISH FIRST FOOTING FOR FOREGROUND-COLOR FOREGROUND-COLOUR FORMAT FREE FROM FULL FUNCTION GENERATE GET GIVING GLOBAL GO GOBACK GREATER GROUP HEADING HIGHLIGHT HIGH-VALUE HIGH-VALUES I-O I-O-CONTROL ID IDENTIFICATION IF IN INDEX INDEXED INDEX-N INDIC INDICATE INDICATOR INDICATORS INITIAL INITIALIZE INITIATE INPUT INPUT-OUTPUT INSPECT INSTALLATION INTO INVALID IS JUST JUSTIFIED KEEP KEY LABEL LAST LD LEADING LEFT LEFT-JUSTIFY LENGTH LENGTH-CHECK LESS LIKE LIMIT LIMITS LINAGE LINAGE-COUNTER LINE LINE-COUNTER LINES LINKAGE LOCALLY LOCK LOW-VALUE LOW-VALUES MEMBER MEMORY MERGE MESSAGE MODE MODIFIED MODIFY MODULES MOVE MULTIPLE MULTIPLY NATIVE NEGATIVE NEXT NO NO-ECHO NONE NOT NULL NULLS NUMBER NUMERIC NUMERIC-EDITED OBJECT-COMPUTER OCCURS OF OFF OMITTED ON ONLY OPEN OPTIONAL OR ORDER ORGANIZATION OTHER OUTPUT OVERFLOW OWNER PACKED-DECIMAL PADDING PAGE PAGE-COUNTER PERFORM PF PH PIC PICTURE PLUS POINTER POSITION POSITIVE PRESENT PRINTING PRIOR PROCEDURE PROCEDURES PROCEED PROCESS PROGRAM PROGRAM-ID PROMPT PROTECTED PURGE QUEUE QUOTE QUOTES RANDOM RD READ READY REALM RECEIVE RECONNECT RECORD RECORD-NAME RECORDS REDEFINES REEL REFERENCE REFERENCE-MONITOR REFERENCES RELATION RELATIVE RELEASE REMAINDER REMOVAL RENAMES REPEATED REPLACE REPLACING REPORT REPORTING REPORTS REQUIRED RERUN RESERVE RESET RETAINING RETRIEVAL RETURN RETURN-CODE REVERSED REVERSE-VIDEO REWIND REWRITE RD RF RH RIGHT RIGHT-JUSTIFY ROLLBACK ROLLING ROUNDED RUN SAME SCREEN SD SEARCH SECTION SECURE SECURITY SEGMENT SEGMENT-LIMIT SELECT SEND SENTENCE SEPARATE SEQUENCE SEQUENTIAL SET SHARED SIGN SIZE SKIP1 SKIP2 SKIP3 SORT SORT-MERGE SORT-RETURN SOURCE SOURCE-COMPUTER SPACE SPACE-FILL SPACES SPECIAL-NAMES STANDARD STANDARD-1 STANDARD-2 START STARTING STATUS STOP STORE STRING SUB-QUEUE-1 SUB-QUEUE-2 SUB-QUEUE-3 SUB-SCHEMA SUBFILE SUBTRACT SUM SUPPRESS SYMBOLIC SYNC SYNCHRONIZED TABLE TALLYING TAPE TENANT TERMINAL TERMINATE TEST TEXT THAN THEN THROUGH THRU TIME TIMES TITLE TO TOP TRAILING TRAILING-SIGN TRANSACTION TRUE TYPE UNDERLINE UNEQUAL UNIT UNSTRING UNTIL UP UPDATE UPON USAGE USAGE-MODE USE USING VALID VALIDATE VALUE VALUES VARYING WAIT WHEN WHEN-COMPILED WITH WITHIN WORDS WORKING-STORAGE WRITE ZERO ZEROES ZERO-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。
部（Division)一部可包括若干节
节（Section)一节可包含若干段
段（Paragraph)一段可包含若干句子
句子（Sentence)一个句子可包含若干语句
语句(Statement)制定计算机完成一定的操作
子句(Clause)制定完成某一方面的功能
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”。
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：
