in reply to Re^4: rand() function on Windows systems (pure Perl)
in thread rand() function on Windows systems

Small correction in the code above:

This line of code :

return ( ( $seed >> 16 ) & 32767 ) / 32767 * $max;

[download]

should be:

return ( ( $seed >> 16 ) & 32767 ) / 32768 * $max;

[download]
The difference can be seen if you don't use the integer (int) function.

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Re^6: rand() function on Windows systems (pure Perl)
by BrowserUk (Patriarch) on Dec 31, 2016 at 03:10 UTC
    The difference can be seen if you don't use the integer (int) function.

    You are absolutely correct++!

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

      One more thing.

      Apparently, the random number seed sub is not necessary the srand operator works the same between the old and the new versions. The simplified code below is enough.

      my $seed = srand( 555 );
print ppRand( ), "\n"; 

sub ppRand
{
    my $max = shift || 1;
    $seed = ( $seed * 214013 + 2531011 );
    return ( ( $seed >> 16 ) & 32767 ) / 32768 * $max;    
}

      [download]
[reply]
[d/l]

        You might just as well do:

        my $seed = 555;
...

        [download]

        It amounts to the same thing.

        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

        Hm. srand always returns 1 regardless of its argument on my system:

        print srand( $_ ) for 1 .. 10;;
1
1
1
1
1
1
1
1
1
1

        [download]
        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority". The enemy of (IT) success is complexity.
        In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]

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