Listing NAMES in order

As a final example of the capabilities of the B-TREE-P system, edit, compile, catalog, and execute the following LIST.NAMES program:

    LIST.NAMES

001 OPEN "B-TREE" TO BFILE ELSE STOP

002 OPEN "NAMES" TO NFILE ELSE STOP

003 ID = "" ; ITEM = ""

004 CRT "ZIP, COMP, OR LNAME":

005 INPUT ROOT

006 CALL BTPFIND(ROOT,BFILE,NFILE,ID,ITEM,NODE,POS)

007 LOOP

008   READ NAMES FROM NFILE, ID ELSE NAMES = ""

009   PRINT ; PRINT ID

010   FOR AMC = 1 TO 6

011     LINE = NAMES<AMC>

012     IF LINE # "" THEN PRINT LINE

013   NEXT AMC

014   CALL BTPSEQ(BFILE, NODE, POS, "NEXT", ID)

015 UNTIL ID = "" DO REPEAT

016 STOP

017 END

LIST.NAMES begins by prompting for a B-tree name. Type the word ZIP, COMP, or LNAME, and LIST.NAMES then immediately lists all items in the NAMES file in the order you selected. Since the appropriate B-tree is used to determine the order of names, LIST.NAMES does not have to wait for a sort to finish before it can begin printing.