Re^4: Old random number generator

Thank you. I don't mind calling my_srand and my_rand (no need to override srand and rand), but I would prefer a solution that works on Linux as well. The * $_[0] / 32767 part appears to be what I needed. print int(winrand()*99/32767) for 0..9 appears to work beautifully. Thank you everyone for your assistance!

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Re^5: Old random number generator by syphilis (Archbishop) on May 10, 2020 at 06:47 UTC
but I would prefer a solution that works on Linux as well On Linux, I'm finding that the behaviour hasn't changed. That is, when I run: `perl -e 'srand(0); print int(rand(99)) for 0 .. 9'` [download] on Ubuntu, I get `1674986577768368673` from (current) perl-5.30.0 all the way back to perl-5.6.2. Or do you mean that you want the output of the one-liner to also be `023647263525973192` on Linux ? That could be tricky ... I'm not sure what that might involve. Here's an Inline::C version that does as you want on Windows - but produces a different sequence of numbers (`83397779901933762754`) on Ubuntu, where RAND_MAX is 2147483647. `use strict; use warnings; use Inline C => <<'EOC'; SV * max_rand() { return newSViv(RAND_MAX); } void my_srand(int seed) { srand(seed); } SV * my_int_rand(IV limit) { return newSViv(rand() * limit / RAND_MAX); } SV * my_float_rand(IV limit) { return newSVnv((NV)rand() * limit / RAND_MAX); } EOC print "RAND_MAX is: ",max_rand(), "\n"; my_srand(0); print my_int_rand(99) for 0 .. 9; #print int(my_float_rand(99)) for 0 .. 9;` [download] Annoyingly on Ubuntu, although perl's rand() output seems constant across different versions of perl, it differs from the output of that script. Another possibility is that Math::Random might provide the functionality you seek. (I took a quick look, couldn't find anything helpful, and gave up ... but I didn't check it out rigorously.) Cheers, Rob	[reply] [d/l] [select]

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Re^5: Old random number generator
by syphilis (Archbishop) on May 10, 2020 at 06:47 UTC

but I would prefer a solution that works on Linux as well

perl -e 'srand(0); print int(rand(99)) for 0 .. 9'
[download]

1674986577768368673

023647263525973192

83397779901933762754

use strict;
use warnings;

use Inline C => <<'EOC';

SV * max_rand() {
  return newSViv(RAND_MAX);
}

void my_srand(int seed) {
  srand(seed);
}

SV * my_int_rand(IV limit) {
  return newSViv(rand() * limit / RAND_MAX);
}

SV * my_float_rand(IV limit) {
  return newSVnv((NV)rand() * limit / RAND_MAX);
}

EOC

print "RAND_MAX is: ",max_rand(), "\n";

my_srand(0);

 print  my_int_rand(99)       for 0 .. 9;
#print int(my_float_rand(99)) for 0 .. 9;
[download]

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