Category : Files from Magazines
Archive   : CL-DEC88.ZIP
Filename : M-EXAMP.BAS

0 ' Illustrates MOVE algorithm (lines 45000-45200)
10 DIM A$(12)
20 FOR J=1 TO 12:READ A$(J):NEXT
25 ' PUT A CLEAR SCREEN FUNCTION HERE (E.G. CLS IN IBM BASIC)
30 PRINT "This program takes the following list of strings (as the array A$() ) :":PRINT:GOSUB 1000:PRINT:PRINT " and moves array elements 7 to 12 to the position following element No. 1 (i.e. START=7, LENGTH=12-7+1=6, FINISH=1)"
40 PRINT:INPUT "Press RETURN to do this",X$:PRINT
50 START=7:LENGTH=6:FINISH=1:GOSUB 45000
55 IF TRUE=0 THEN PRINT "Error";:ELSE GOSUB 1000
200 END
998 '**************************************************************************
999 'Display strings
1000 PRINT "Array element No.";TAB(40);"String"
1005 PRINT STRING$(55,"-")
1010 FOR J=1 TO 12:PRINT J;TAB(40);A$(J):NEXT
1020 RETURN
1021 '*************************************************************************
1999 'Example data
2000 DATA "This","the","divide","and","swap","technique.","tests","the","MOVE","algorithm","which","uses"
2001 '*************************************************************************
44995 'MOVE procedure (pass START,LENGTH & FINISH to routine. Returns TRUE=0 if error))
44996 ' START is start position of 1st element of block
44997 ' LENGTH is the no. of array elements in the block
44998 ' The block is moved to the position following element No. FINISH
44999 '
45000 TRUE=1
45010 IF START>FINISH THEN X=START-FINISH-1:Y=START:START=FINISH+1:FINISH=Y+LENGTH-1:LENGTH=X
45020 IF (FINISH>START AND FINISH 45030 S=START
45040 WHILE LENGTH<>0:LPREV=LENGTH
45050 X=FINISH+1-(S+LENGTH):IF X=0 THEN GOTO 45100
45060 IF X=LENGTH THEN GOSUB 45200:GOTO 45100
45070 IF LENGTH 45080 IF LENGTH>X THEN L1=LENGTH-X:LENGTH=X:GOSUB 45200:S=S+LENGTH:LENGTH=L1
45090 WEND
45100 RETURN
45110 '........................................................................
45199 'Exchange LENGTH array elements starting at element S with block starting at element S+PREV
45200 FOR J=S TO S+LENGTH-1:SWAP A$(J),A$(J+LPREV):NEXT:RETURN