Initial data commit

Task/Sorting-algorithms-Shell-sort/IS-BASIC/sorting-algorithms-shell-sort.basic

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+100 PROGRAM "ShellSrt.bas"
+110 RANDOMIZE
+120 LET N=20 ! Number of elements
+130 NUMERIC ARRAY(1 TO N)
+140 CALL INIT(ARRAY)
+150 CALL WRITE(ARRAY)
+160 CALL SHELLSORT(ARRAY)
+170 CALL WRITE(ARRAY)
+180 DEF INIT(REF A)
+190   FOR I=LBOUND(A) TO UBOUND(A)
+200     LET A(I)=RND(N)+1
+210   NEXT
+220 END DEF
+230 DEF WRITE(REF A)
+240   FOR I=LBOUND(A) TO UBOUND(A)
+250     PRINT A(I);
+260   NEXT
+270   PRINT
+280 END DEF
+290 DEF SHELLSORT(REF A)
+300   LET D=2^INT(LOG(N)/LOG(2))-1
+310   DO
+320     LET I=1
+330     DO WHILE I<=D AND I+D<=N
+340       FOR J=I+D TO N STEP D
+350         LET AH=A(J):LET BH=J-D
+360         DO WHILE BH>0 AND AH<A(BH)
+370           LET A(BH+D)=A(BH):LET BH=BH-D
+380         LOOP
+390         LET A(BH+D)=AH
+400       NEXT
+410       LET I=I+1
+420     LOOP
+430     LET D=INT(D/2)
+440   LOOP WHILE D>0
+450 END DEF