Character string handling has become a powerful tool in the RPG programmer's toolbox. The following three techniques offer you a few shortcuts for jobs that used to be very tedious.

To find out how many characters exist in an alphanumeric field, use the code shown in the first example in 3. The Check Reverse (CHEKR) operation will look for the last nonblank character in the input field (INPFLD) and return its position in the variable X. The result of this operation is that the value in field X will be the length of the data in the field INPFLD.

To find out how many characters exist in an alphanumeric field, use the code shown in the first example in Figure 3. The Check Reverse (CHEKR) operation will look for the last nonblank character in the input field (INPFLD) and return its position in the variable X. The result of this operation is that the value in field X will be the length of the data in the field INPFLD.

To left justify data in an alphanumeric field, remove leading blanks using the code in the second example in 3. The CHECK operation will locate the first nonblank character in INPFLD and put its position into variable X. The subsequent Substring (SUBST) operation will move the INPFLD data back into itself beginning at the first nonblank character address. The P extender is specified so all characters beyond those that were moved will be replaced with blanks.

To left justify data in an alphanumeric field, remove leading blanks using the code in the second example in Figure 3. The CHECK operation will locate the first nonblank character in INPFLD and put its position into variable X. The subsequent Substring (SUBST) operation will move the INPFLD data back into itself beginning at the first nonblank character address. The P extender is specified so all characters beyond those that were moved will be replaced with blanks.

To right adjust data in an alphanumeric field, remove trailing blanks using the code in the third example in 3. Use the CHEKR operation to find the last nonblank character. The result in variable X represents the length of the field. The contents of INPFLD are then saved in a work field (WRKFLD).

To right adjust data in an alphanumeric field, remove trailing blanks using the code in the third example in Figure 3. Use the CHEKR operation to find the last nonblank character. The result in variable X represents the length of the field. The contents of INPFLD are then saved in a work field (WRKFLD).

Subtract the length of the data (currently stored in variable X) from the field length (stored in FLDLEN) and return the results back to variable X. The result in variable X is now the number of trailing blanks that exist in the input field.

Clear the original input field (INP-FLD) and then perform a concatenation (CAT) operation from WRKFLD back into INPFLD using the number of trailing blanks as the new number of leading blanks.

Swapping the number of trailing blanks for the number of leading blanks right adjusts INPFLD.

? Doug Pence

TechTalk: RPG String Calculations

Figure 3: RPG String Calculations

 *. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7 * * Example 1 - Calculate data length C ' ' CHEKRINPFLD X 20 * * Example 2 - Left justify data C ' ' CHECKINPFLD X 20 C SUBSTINPFLD:X INPFLD P * * Example 3 - Right justify data C ' ' CHEKRINPFLD X 20 C MOVELINPFLD WRKFLD 20 P C FLDLEN SUB X X C MOVE *BLANKS INPFLD 20 C CAT WRKFLD:X INPFLD *. 1 ...+... 2 ...+... 3 ...+... 4 ...+... 5 ...+... 6 ...+... 7