100 PROGRAM "Permutat.bas"
110 LET N=4 ! Number of elements
120 NUMERIC T(1 TO N)
130 FOR I=1 TO N
140   LET T(I)=I
150 NEXT
160 LET S=0
170 CALL PERM(N)
180 PRINT "Number of permutations:";S
190 END
200 DEF PERM(I)
210   NUMERIC J,X
220   IF I=1 THEN
230     FOR X=1 TO N
240       PRINT T(X);
250     NEXT
260     PRINT :LET S=S+1
270   ELSE
280     CALL PERM(I-1)
290     FOR J=1 TO I-1
300       LET C=T(J):LET T(J)=T(I):LET T(I)=C
310       CALL PERM(I-1)
320       LET C=T(J):LET T(J)=T(I):LET T(I)=C
330     NEXT
340   END IF
350 END DEF