Re: srand producing the same sequence of random numbers

AFAIK, the only purpose for srand() is to be able to obtain a repeatable set of “random” numbers, e.g. for certain esoteric statistical sampling purposes or some similar special purpose. The intended behavior is exactly what you saw: after re-seeding, the pseudo-random sequence repeats.

The random number generator does not need to be re-seeded, ever, in normal practice.

The standard random number generator is not suitable for cryptographic purposes.

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Re^2: srand producing the same sequence of random numbers by ikegami (Patriarch) on Oct 12, 2010 at 06:43 UTC
The random number generator does not need to be re-seeded, ever, in normal practice. Every interpreter needs to be seeded. Perl will do that automatically, except when the interpreter is cloned by `fork`. `$ perl -e' rand(10); if (my $pid = fork()) { waitpid($pid, 0); } local ($,, $\) = (", ", "\n"); print map int(rand(10)), 1..10; ' 8, 3, 9, 8, 8, 2, 3, 8, 4, 8 8, 3, 9, 8, 8, 2, 3, 8, 4, 8` [download]	[reply] [d/l] [select]

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Re^2: srand producing the same sequence of random numbers
by ikegami (Patriarch) on Oct 12, 2010 at 06:43 UTC

The random number generator does not need to be re-seeded, ever, in normal practice.

Every interpreter needs to be seeded. Perl will do that automatically, except when the interpreter is cloned by fork.

$ perl -e'
   rand(10);
   if (my $pid = fork()) { waitpid($pid, 0); }
   local ($,, $\) = (", ", "\n");
   print map int(rand(10)), 1..10;
'
8, 3, 9, 8, 8, 2, 3, 8, 4, 8
8, 3, 9, 8, 8, 2, 3, 8, 4, 8
[download]

[reply]
[d/l]
[select]