Example of 1 vs 0 based indexing.

guess_number.jl

#!/usr/bin/env julia

range = 1:100
big = range[end]
small = range[1]

function guess()
    (small + big) >> 1
end

function bigger()
    global small = guess() + 1
    guess()
end

function smaller()
    global big = guess() - 1
    guess()
end

function start_over()
    global big = range[end]
    global small = range[1]
    guess()
end

guess_number.py

#!/usr/bin/env python3

my_range = range(1, 101)
big = my_range[-1]
small = my_range[0]

def guess():
    return (small + big) >> 1

def bigger():
    global small
    small = guess() + 1
    return guess()

def smaller():
    global big
    big = guess() -1
    return guess()

def start_over():
    global big, small
    big = my_range[-1]
    small = my_range[0]
    return guess()

Example:

ismaelvc@toybox ~> julia
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" to list help topics
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.3.0-prerelease+1629 (2014-02-18 19:07 UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit 7d997ed* (2 days old master)
|__/                   |  i686-pc-linux-gnu

julia> include("guess_number.jl");

julia> guess()
50

julia> bigger()
75

julia> smaller()
62

julia> smaller()
56

julia>