100 REM Knuth shuffle
110 RANDOMIZE
120 DIM B(51)
130 PRINT "BEFORE:"
140 FOR L0 = 0 TO 51
150   LET B(L0) = L0
160   PRINT B(L0);" ";
170 NEXT L0
180 FOR L0 = 51 TO 0 STEP -1
190   LET C = INT(RND*(L0+1))
200   IF C <> L0 THEN 220
210   GOTO 250
220   LET T = B(C)
230   LET B(C) = B(L0)
240   LET B(L0) = T
250 NEXT L0
260 PRINT
270 PRINT
280 PRINT "AFTER:"
290 FOR L0 = 0 TO 51
300   PRINT B(L0);" ";
310 NEXT L0
320 PRINT
330 END