1000     DIM  Q(5)
1001 REM
1002 REM INITIALIZE QUEUE TO EMPTY STATE
1003 REM
1010     FOR J2 = 1 TO 5
1020     Q(J2) = -9
1030     NEXT J2
1031 REM
1032 REM INITIALIZE HEAD AND TAIL POINTERS
1033 REM TO HEAD OF QUEUE LOCATION
1034 REM
1040     H =  5
1050     T =  5
1051 REM
1052 REM START OF MAIN SIMULATION LOOP
1053 REM
1060     FOR J3 = 1 TO 10
1061 REM
1062 REM GENERATE A RANDOM NUMBER TO DETERMINE
1063 REM AN INSERTION WHEN N <= 5
1064 REM  A DELETION  WHEN N >= 6
1065 REM
1070     N = INT ( RND (1) * 10 ) + 1
1080     IF N <= 5 THEN GOSUB 1900
1090     IF N >= 6 THEN GOSUB 2110
1091 REM
1092 REM PRINT QUEUE CONTENTS
1093 REM PRINT TAIL AND KEAD POINTER VALUES
1094 REM
1100     FOR J4 = 1 TO 5
1110     PRINT Q(J4);
1120     NEXT J4
1130     PRINT " TAIL AT"; T; " HEAD AT"; H
1131 REM
1132 REM END OF MAIN SIMULATION LOOP
1133 REM
1140     NEXT J3
1150     STOP
1151 REM
1152 REM   I N S E R T I O N   R O U T I N E
1153 REM
1154 REM CHECK TAIL AND HEAD POINTER VALUES
1155 REM
1900     IF H = T THEN GOTO 1970
1910     IF H < T THEN GOTO 2030
1920     IF T >= 1 THEN GOTO 2030
1930     IF H = 5 THEN GOTO 2080
1931 REM
1932 REM INSERT ITEM AT Q(H)
1933 REM SINCE QUEUE IS EMPTY
1934 REM
1940     Q(5) = N
1950     T = 4
1960     GOTO 2050
1970     IF T <> 0 THEN GOTO 2000
1971 REM
1972 REM RESET POINTERS TO HEAD OF QUEUE
1973 REM
1980     H = 5
1990     T = 5
1991 REM
1992 REM CHECK IF Q(T) EMPTY FOR POSSIBLE INSERT
1993 REM
2000     IF Q(T) <> -9 THEN GOTO 2080
2010     H = 5
2020     T = 5
2021 REM
2022 REM NORMAL TAIL INSERTION
2023 REM
2030     Q(T) = N
2040     T = T - 1
2050     PRINT " "
2060     PRINT "ARRIVAL"
2070     RETURN
2080     PRINT " "
2090     PRINT "OVERFLOW"
2100     RETURN
2101 REM
2102 REM   D E L E T I O N   R O U T I N E
2103 REM
2104 REM CHECK POINTER VALUES FOR POSSIBLE DELETE
2105 REM
2110     IF H = T THEN GOTO 2150
2120     IF H > 0 THEN GOTO 2190
2130     H = 5
2140     GOTO 2180
2150     IF H <> 0 THEN GOTO 2180
2160     H =  5
2170     T = 5
2171 REM
2172 REM DELETE FROM Q(H) IF Q(H) HAS AN ITEM
2173 REM ELSE, QUEUE IS EMPTY, I.E. UNDERFLOW
2174 REM
2180     IF Q(H) = -9 THEN GOTO 2240
2190     Q(H) = -9
2200     H = H - 1
2201 REM
2202 REM RESET POINTERS FOR NEXT DELETE
2203 REM
2210     IF H <> 0 THEN GOTO 2260
2220     H =  5
2230     RETURN
2240     PRINT " "
2250     PRINT "UNDERFLOW"
2260     RETURN
2270 END