GENERAL LEVEL NUMBERS IN COBOL
COBOL defines data items in Levels
01 level – Topmost level.
- We can use this for an Individual data item or a group item. There cannot be another 01 levels within a 01 level.
Example: 01 EMP-ID PIC 9(5). Here this an is individual variable and no sub-items are present below this.
- This can also use for Group data item. Group data item does not have a picture clause. It has elementary items below it.
Example: 01 EMP-RECORD. —- This is a group item
05 EMP-ID PIC 9(5). —Elementary items
05 EMP-NAME. — This is also a group item
10 FIRST-NAME PIC A(15).
10 LAST-NAME PIC A(15).
Level numbers with the same numeric value are considered at the same level.
As we move down, the level number must increase.
Level 01-49 is for general purpose
SPECIAL LEVEL NUMBERS IN COBOL
Special purpose Level: 66, 77, 88
66 level – Used for RENAMES clause. and 66 levels should not have a picture clause.
Example – 01 EMP-REC.
05 EMP-ID PIC 9(5).
05 EMP-NAME PIC A(10).
05 EMP-BIRTH-DATE PIC X(10).
66 EMP-DETAIL RENAMES EMP-ID THRU EMP-NAME.
77 – Normally we should avoid using 77 levels. we need use for an Individual data item or elementary data item. And we can’t subdivide it further.
88 level– This is used for conditional processing. 88 level must be coded under a group item. It works on the principle of true or false.
Example: 01 CHECK-DAY.
05 DAY PIC X(3).
88 MONDAY VALUE ‘MON’.
88 TUESDAY VALUE ‘TUE’.
88 WEDNESDAY VALUE ‘WED’.
88 THURSDAY VALUE ‘THU’.
88 FRIDAY VALUE ‘FRI’.
88 SATURDAY VALUE ‘SAT’.
88 SUNDAY VALUE ‘SUN’.