option nolet
randomize
print "**************************************************"
print "* programming :truebasic, random_walk 'version 1'*"
print "* peter.vlasschaert@gmail.com,22/01/2020         *"
print "**************************************************"
!*********************************************************
! see website :
! maxima :programming :random walk ([N,S,W,E]),version 1.0
! peter.vlasschaert@gmail.com,21/01/2019.
!*********************************************************
print
input prompt " example = 1, random = 2 => ":s
print
x = 0
y = 0 
print "***********"
print " input =>  "
print "***********"
print " x = ";x
print " y = ";y
print
dim l(1)
if s = 2 then
nn =10
mat redim l(nn)
for i=1 to nn
  l(i) =int (4*rnd)+1
next i
else 
nn = 8
mat redim l(nn)
l(1) = 1
l(2) = 4
l(3) = 4
l(4) = 2
l(5) = 4
l(6) = 1
l(7) = 1
l(8) = 4
END IF

print "***************************"
print " random list ={1,2,3,4} => "
print "***************************"
a0$ = ","
a1$ = "North= N =1"
a2$ = "South= S =2"
a3$ = "West = W =3"
a4$ = "East = E =4"
print a1$ & a0$ & a2$ & a0$ & a3$ & a0$ & a4$
print
mat print l
! algo :
for i=1 to nn
call random_walk(l(),i,x,y)
next i
! end algo
print "***********"
print " output => "
print "***********"
IF s =1 then
print "*****************"
print "*example :output*"
print "*****************"
print
b1$ = "N"
b2$ = "S"
b3$ = "W"
b4$ = "E"
print "****************************************************"
print " list = direction for home (0,0) to some place (4,2)"
print "****************************************************"
print
print "***************"
print "N,E,E,S,E,N,N,E"
print "***************"
print
END IF
print
print " x = ";x
print " y = ";y
end

sub random_walk(l(),k,x,y)
! How to use 'ELSE IF'
IF 1 = l(k) THEN      ! North
y = y+1
ELSE IF 2 = l(k) then ! South
y = y-1
ELSE IF 3 = l(k) then ! West
x = x-1
ELSE                  ! East
x = x+1
END IF
end sub