Position 45 is used to reset a numeric field to zeros or a character, graphic, or UCS-2 field to blanks. Date, time, and timestamp fields are reset to their default values.
If the field is conditioned by indicators in positions 21 through 29, the blank after is also conditioned. This position must be blank for look-ahead, user date reserved words, *PLACE, named constants, and literals.
Resetting fields to zeros may be useful in total output when totals are accumulated and written for each control group in a program. After the total is accumulated and written for one control group, the total field can be reset to zeros before accumulation begins on the total for the next control group.
If blank after (position 45) is specified for a field to be written more than once, the B should be entered on the last line specifying output for that field, or else the field named will be printed as the blank-after value for all lines after the one doing the blank after.