00000000: 20 20 20 20 20 20 20 20 20 20 20 D3 45 54 20 C6 | .ET .|
00000010: 49 4C 45 20 D0 4F 49 4E 54 45 52 53 20 20 20 20 |ILE .OINTERS |
00000020: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000030: 20 20 20 2D 2D 2D 2D 2D 2D 2D 2D 2D 2D 2D 2D 2D | -------------|
00000040: 2D 2D 2D 2D 20 20 20 20 20 20 20 20 20 20 20 20 |---- |
00000050: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000060: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000070: 20 20 20 20 20 20 20 20 D4 48 45 53 45 20 4F 50 | .HESE OP|
00000080: 54 49 4F 4E 53 20 41 4C 4C 4F 57 20 59 4F 55 20 |TIONS ALLOW YOU |
00000090: 54 4F 20 4D 41 4E 49 50 55 4C 41 54 45 20 20 20 |TO MANIPULATE |
000000A0: 54 48 45 20 46 49 4C 45 20 50 4F 49 4E 54 45 52 |THE FILE POINTER|
000000B0: 53 20 53 4F 20 54 48 41 54 20 59 4F 55 20 43 41 |S SO THAT YOU CA|
000000C0: 4E 20 44 45 41 4C 20 20 57 49 54 48 20 41 20 53 |N DEAL WITH A S|
000000D0: 50 45 43 49 46 49 43 20 52 45 43 4F 52 44 20 49 |PECIFIC RECORD I|
000000E0: 4E 20 41 20 46 49 4C 45 2E 20 20 20 20 20 20 20 |N A FILE. |
000000F0: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000100: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000110: 20 20 20 20 20 20 20 20 CF 50 54 49 4F 4E 20 31 | .PTION 1|
00000120: 20 2D 20 53 45 54 53 20 54 48 45 20 50 4F 49 4E | - SETS THE POIN|
00000130: 54 45 52 20 54 4F 20 54 48 45 20 4E 45 58 54 20 |TER TO THE NEXT |
00000140: 52 45 43 4F 52 44 20 54 4F 20 42 45 20 57 52 49 |RECORD TO BE WRI|
00000150: 54 54 45 4E 2E 20 20 20 20 20 20 20 20 20 20 20 |TTEN. |
00000160: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000170: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000180: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000190: CF 50 54 49 4F 4E 20 32 20 2D 20 53 45 54 53 20 |.PTION 2 - SETS |
000001A0: 54 48 45 20 50 4F 49 4E 54 45 52 20 54 4F 20 54 |THE POINTER TO T|
000001B0: 48 45 20 46 49 52 53 54 52 45 43 4F 52 44 20 54 |HE FIRSTRECORD T|
000001C0: 48 41 54 20 57 41 53 20 28 4F 52 20 49 46 20 41 |HAT WAS (OR IF A|
000001D0: 20 4E 45 57 20 46 49 4C 45 20 2C 20 49 53 20 20 | NEW FILE , IS |
000001E0: 41 42 4F 55 54 20 54 4F 20 42 45 29 20 57 52 49 |ABOUT TO BE) WRI|
000001F0: 54 54 45 4E 2E 20 20 20 20 20 20 20 20 20 20 20 |TTEN. |
00000200: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000210: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000220: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000230: CF 50 54 49 4F 4E 20 33 20 2D 20 53 45 54 53 20 |.PTION 3 - SETS |
00000240: 54 48 45 20 50 4F 49 4E 54 45 52 20 42 41 43 4B |THE POINTER BACK|
00000250: 20 42 59 20 4F 4E 45 20 52 45 43 4F 52 44 2E 20 | BY ONE RECORD. |
00000260: D2 45 4D 45 4D 42 45 52 20 54 48 41 54 20 41 46 |.EMEMBER THAT AF|
00000270: 54 45 52 20 41 20 52 45 41 44 20 4F 52 20 41 20 |TER A READ OR A |
00000280: 57 52 49 54 45 20 54 48 45 20 50 4F 49 4E 54 45 |WRITE THE POINTE|
00000290: 52 20 49 53 20 53 45 54 20 54 4F 20 54 48 45 20 |R IS SET TO THE |
000002A0: 4E 45 58 54 20 20 20 20 52 45 43 4F 52 44 2C 20 |NEXT RECORD, |
000002B0: 54 48 45 52 45 46 4F 52 45 20 54 4F 20 57 52 49 |THEREFORE TO WRI|
000002C0: 54 45 20 44 41 54 41 20 42 41 43 4B 20 54 4F 20 |TE DATA BACK TO |
000002D0: 54 48 45 20 52 45 43 4F 52 44 20 49 54 20 43 41 |THE RECORD IT CA|
000002E0: 4D 45 20 46 52 4F 4D 20 59 4F 55 20 4D 55 53 54 |ME FROM YOU MUST|
000002F0: 20 55 53 45 20 20 20 20 54 48 49 53 20 4F 50 54 | USE THIS OPT|
00000300: 49 4F 4E 2E 20 20 20 20 20 20 20 20 20 20 20 20 |ION. |
00000310: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000320: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000330: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000340: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000350: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000360: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000370: CF 50 54 49 4F 4E 20 34 20 2D 20 D4 48 49 53 20 |.PTION 4 - .HIS |
00000380: 4F 50 54 49 4F 4E 20 41 4C 4C 4F 57 53 20 59 4F |OPTION ALLOWS YO|
00000390: 55 20 54 4F 20 55 53 45 54 48 45 20 56 41 4C 55 |U TO USETHE VALU|
000003A0: 45 20 4F 46 20 41 20 4E 55 4D 45 52 49 43 20 46 |E OF A NUMERIC F|
000003B0: 49 45 4C 44 20 41 53 20 41 20 46 49 4C 45 20 20 |IELD AS A FILE |
000003C0: 50 4F 49 4E 54 45 52 2E 20 D4 48 49 53 20 57 4F |POINTER. .HIS WO|
000003D0: 55 4C 44 20 41 4C 4C 4F 57 20 59 4F 55 20 54 4F |ULD ALLOW YOU TO|
000003E0: 20 43 52 45 41 54 45 20 41 4E 20 49 4E 44 45 58 | CREATE AN INDEX|
000003F0: 20 53 54 52 55 43 54 55 52 45 20 54 4F 20 59 4F | STRUCTURE TO YO|
00000400: 55 52 20 46 49 4C 45 53 2E 20 20 20 20 20 20 20 |UR FILES. |
00000410: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000420: 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000430: 20 20 20 20 20 20 20 20 CF 50 54 49 4F 4E 20 35 | .PTION 5|
00000440: 20 2D 20 D4 48 49 53 20 49 53 20 54 48 45 20 4F | - .HIS IS THE O|
00000450: 50 50 4F 53 49 54 45 20 4F 46 20 54 48 45 20 20 |PPOSITE OF THE |
00000460: 50 52 45 56 49 4F 55 53 20 4F 50 54 49 4F 4E 20 |PREVIOUS OPTION |
00000470: 41 4E 44 20 57 4F 55 4C 44 20 42 45 20 55 53 45 |AND WOULD BE USE|
00000480: 44 20 46 49 52 53 54 2E C9 54 20 41 4C 4C 4F 57 |D FIRST..T ALLOW|
00000490: 53 20 59 4F 55 20 54 4F 20 48 4F 4C 44 20 54 48 |S YOU TO HOLD TH|
000004A0: 45 20 56 41 4C 55 45 20 4F 46 20 54 48 45 20 20 |E VALUE OF THE |
000004B0: 46 49 4C 45 20 50 4F 49 4E 54 45 52 20 49 4E 20 |FILE POINTER IN |
000004C0: 41 20 4E 55 4D 45 52 49 43 20 46 49 45 4C 44 20 |A NUMERIC FIELD |
000004D0: 57 49 54 48 49 4E 20 20 41 20 46 49 4C 45 2E 20 |WITHIN A FILE. |
000004E0: D4 48 49 53 20 49 4E 44 45 58 20 43 4F 55 4C 44 |.HIS INDEX COULD|
000004F0: 20 54 48 45 4E 20 42 45 20 53 4F 52 54 45 44 20 | THEN BE SORTED |
00000500: 41 4E 44 20 53 54 49 4C 4C 20 52 45 46 45 52 45 |AND STILL REFERE|
00000510: 4E 43 45 20 54 48 45 20 4F 52 49 47 49 4E 41 4C |NCE THE ORIGINAL|
00000520: 20 46 49 4C 45 20 20 20 50 4F 49 4E 54 45 52 2E | FILE POINTER.|
00000530: 85 FF 0D |... |
SET FILE POINTERS
-----------------
THESE OPTIONS ALLOW YOU TO MANIPULATE
THE FILE POINTERS SO THAT YOU CAN DEAL
WITH A SPECIFIC RECORD IN A FILE.
OPTION 1 - SETS THE POINTER TO THE NEXT
RECORD TO BE WRITTEN.
OPTION 2 - SETS THE POINTER TO THE FIRST
RECORD THAT WAS (OR IF A NEW FILE , IS
ABOUT TO BE) WRITTEN.
OPTION 3 - SETS THE POINTER BACK BY ONE
RECORD. REMEMBER THAT AFTER A READ OR A
WRITE THE POINTER IS SET TO THE NEXT
RECORD, THEREFORE TO WRITE DATA BACK TO
THE RECORD IT CAME FROM YOU MUST USE
THIS OPTION.
OPTION 4 - THIS OPTION ALLOWS YOU TO USE
THE VALUE OF A NUMERIC FIELD AS A FILE
POINTER. THIS WOULD ALLOW YOU TO CREATE
AN INDEX STRUCTURE TO YOUR FILES.
OPTION 5 - THIS IS THE OPPOSITE OF THE
PREVIOUS OPTION AND WOULD BE USED FIRST.
IT ALLOWS YOU TO HOLD THE VALUE OF THE
FILE POINTER IN A NUMERIC FIELD WITHIN
A FILE. THIS INDEX COULD THEN BE SORTED
AND STILL REFERENCE THE ORIGINAL FILE
POINTER....
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