Data commit

Task/Binary-search/GW-BASIC/binary-search.basic

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+10 REM Binary search
+20 DIM A(10)
+30 N% = 10
+40 FOR I% = 0 TO 9: READ A(I%): NEXT I%
+50 REM Sorted data
+60 DATA -31, 0, 1, 2, 2, 4, 65, 83, 99, 782
+70 X = 2: GOSUB 500
+80 GOSUB 200
+90 X = 5: GOSUB 500
+100 GOSUB 200
+110 END
+190 REM Print result
+200 PRINT X;
+210 IF INDX% >= 0 THEN PRINT "is at index"; STR$(INDX%);"." ELSE PRINT "is not found."
+220 RETURN
+480 REM Binary search algorithm
+490 REM N% - number of elements; X - searched element; Result: INDX% - index of X
+500 L% = 0: H% = N% - 1: FOUND% = 0
+510 WHILE (L% <= H%) AND NOT FOUND%
+520  M% = L% + (H% - L%) \ 2
+530  IF A(M%) < X THEN L% = M% + 1 ELSE IF A(M%) > X THEN H% = M% - 1 ELSE FOUND% = -1
+540 WEND
+550 IF FOUND% = 0 THEN INDX% = -1 ELSE INDX% = M%
+560 RETURN