' Snakes and Ladders simulation
' Start off the board (position = 0)

' Only end when landing exactly on 100. If over roll, move back
' the surplus amount.  So on 99, roll 4 (=103).  Move forward 1 +
' (=100) then back 3. Final square = 97.


option base 1  ' Board starts at square 1
option default integer 'variables integers by default
dim board(100)
dim bins(500)
dim binindex(500)

' Pre populate board with squares that equal its number

for x = 1 to 100
 let board(x) = x
next x

' load in structure of snakes and ladders
for y = 1 to 18
 read start,finish
 let board(start) = finish
next y

'reset rolls and set number of simulations
let roll_total = 0
let maxit = 10000 '10,000 gives a consistent overall average
dim rolls(maxit)


print "Simulating"maxit " individual games of Snakes and ladders."

'set up the simulation
for runs = 1 to maxit
 let position = 0 ' start off the board
 let currnetroll = 0


 do  'individual games
   currentroll = int((rnd*6))+1
   position = position + currentroll
   if position = 100 then exit do
   if position > 100 then position = 100 - (position - 100)
   position = board(position)
   rolls(runs) = rolls(runs) + 1 'keep count of number of rolls
 loop while position <100
   bins(rolls(runs)) = bins(rolls(runs)) + 1  
next runs

roll_mean = math(mean rolls())
roll_median = math(median rolls())
roll_max = math(max rolls())
roll_min = math(min rolls())

sort bins(), binindex()

roll_modal =  binindex(500)

print""
print "Mode:"roll_modal, "Mean:" roll_mean, "Median:" roll_median, "Max:" roll_max, "Min:" roll_min


'ladders and then snakes
'data 5,23,7,55,13,31,20,39,33,69,37,86,57,83,61,99,71,92
'data 45,9,47,11,63,43,74,49,77,51,81,26,88,3,94,53,96,41

'board 2
data 5,17,13,31,21,37,28,64,48,52,54,91,62,98,76,86
data 26,7,33,10,57,53,59,24,67,36,71,49,77,41,84,61,92,73,97,66

option base 1
dim board(100)      'the 100 squares of the board
dim bins(500)       'gather statistics of the runs (is zero'ed at creation)

' Snakes and Ladders simulation
' Pre populate board with squares that equal its number

for x = 1 to 100
let board(x) = x
next x

' load in structure of snakes and ladders from DATA statements
for y = 1 to 18
read start, finish
let board(start) = finish
next y

'reset rolls and set number of simulations
let roll_total = 0
let maxit = 10000 '10,000 gives a consistent overall average

print "Simulating"maxit " individual games of Snakes and ladders."

'set up the simulation
for runs = 1 to maxit
let position = 1
let rolls = 0
 
do  'individual games
  roll = int((rnd*5)+0.5)+1
  position = position + roll
  if position >= 100 then exit do
  position = board(position)
  rolls = rolls + 1
loop while position <100

roll_total = roll_total+rolls
bins(rolls)=bins(rolls)+1

next runs

print "Overall average after" maxit " rolls is" int((roll_total/maxit)+0.5) " rolls"

' calculate modal% value (the index in the array) and qty (the number of times it is ' rolled.
qty=math(max bins(),modal%)
print "modal value = ";modal%;" occurring ";qty;" times"


'ladders and then snakes
data 5,23,7,55,13,31,20,39,33,69,37,86,57,83,61,99,71,92
data 45,9,47,11,63,43,74,49,77,51,81,26,88,3,94,53,96,41