#include once "knuthshuf.bas"   'use the routines in https://rosettacode.org/wiki/Knuth_shuffle#FreeBASIC

function gus( i as long, strat as boolean ) as long
    if strat then return i
    return 1+int(rnd*100)
end function

sub trials( byref c_success as long, byref c_fail as long, byval strat as boolean )
        dim as long i, j, k, guess, drawer(1 to 100)
    for i = 1 to 100
        drawer(i) = i
    next i
    for j = 1 to 1000000 'one million trials of prisoners
        knuth_up( drawer() )  'shuffles the cards in the drawers
            for i = 1 to 100 'prisoner number
            guess = gus(i, strat)
            for k = 1 to 50 'each prisoner gets 50 tries
                if drawer(guess) = i then goto next_prisoner
                guess = gus(drawer(guess), strat)
            next k
            c_fail += 1
            goto next_trial
            next_prisoner:
        next i
        c_success += 1
        next_trial:
    next j
end sub

randomize timer
dim as long c_fail=0, c_success=0

trials( c_success, c_fail, false )

print using "For prisoners guessing randomly we had ####### successes and ####### failures.";c_success;c_fail

c_success = 0
c_fail = 0

trials( c_success, c_fail, true )

print using "For prisoners using the strategy we had ####### successes and ####### failures.";c_success;c_fail