Pseudo-random numbers/Middle-square method

To generate a sequence of n-digit pseudorandom numbers, an n-digit starting value is created and squared, producing a 2n-digit number. If the result has fewer than 2n digits, leading zeroes are added to compensate. The middle n digits of the result would be the next number in the sequence and returned as the result. This process is then repeated to generate more numbers.

Middle-square_method Generator
The Method

Pseudo code

var seed = 675248
function random()
    var s = str(seed * seed) 'str: turn a number into string
    do while not len(s) = 12
        s = "0" + s          'add zeroes before the string
    end do
    seed = val(mid(s, 4, 6)) 'mid: string variable, start, length
                             'val: turn a string into number
    return seed
end function

Middle-square method use

for i = 1 to 5
    print random()
end for

Task

Generate a class/set of functions that generates pseudo-random

numbers (6 digits) as shown above.

Show the first five integers generated with the seed 675248 as shown above.

Show your output here, on this page.

ALGOL 68

Uses (long) integers. <lang algol68>BEGIN # generate random numbers by the middle-square method #

   INT seed := 675248;
   # returns the next middle-square random number #
   PROC ms random = INT: seed := SHORTEN( ( ( LONG INT( seed ) * LONG INT( seed ) ) OVER 1000 ) MOD 1 000 000 );
   # test the ms random procedure #
   FOR i TO 5 DO
       print( ( " ", whole( ms random, 0 ) ) )
   OD

END</lang>

Output:

 959861 333139 981593 524817 432883

FreeBASIC

<lang freebasic>Dim Shared seed As Integer = 675248 Dim i As Integer Declare Function Rand As Integer For i = 1 To 5 Print Rand Next i Sleep

Function Rand As Integer Dim s As String s = Str(seed ^ 2) Do While Len(s) <> 12 s = "0" + s Loop seed = Val(Mid(s, 4, 6)) Rand = seed End Function </lang>

Perl

<lang perl>#!/usr/bin/perl

use strict; # https://rosettacode.org/wiki/Pseudo-random_numbers/Middle-square_method use warnings;

sub msq

 {
 use feature qw( state );
 state $seed = 675248;
 $seed = sprintf "%06d", $seed ** 2 / 1000 % 1e6;
 }

print msq, "\n" for 1 .. 5;</lang>

Output:

Phix

You don't actually have to use strings, but should you so desire the commented-out line gives exactly the same results. Output matches Python.

with javascript_semantics
integer seed = 675248
function random()
    seed = remainder(floor(seed*seed/1000),1e6)
--  seed = to_integer(sprintf("%012d",seed*seed)[4..9])
    return seed
end function
for i=1 to 5 do
    ?random()
end for

Python

<lang python>seed = 675248 def random():

   global seed
   s = str(seed ** 2)
   while len(s) != 12:
       s = "0" + s
   seed = int(s[3:9])
   return seed

for i in range(0,5):

   print(random())

</lang>

Output:

Raku

<lang perl6>sub msq {

   state $seed = 675248;
   $seed = $seed² div 1000 mod 1000000;

}

say msq() xx 5;</lang>

Output:

(959861 333139 981593 524817 432883)

Wren

<lang ecmascript>var random = Fn.new { |seed| ((seed * seed)/1e3).floor % 1e6 }

var seed = 675248 for (i in 1..5) System.print(seed = random.call(seed))</lang>

Output: