Alternative rand()-algorithm?

[Kristofer Berggren]

Hi,

I'm developing a simple application which uses rand() frequently, and
I was just wondering if there are any alternatives to generating random
numbers other than the in-built function in C? I'm using GNU C/C++
compiler 3.3.1.

rand() works okay for me, but I suppose it has its limitations?

/Kristofer

 

[Ben Pfaff]

I'm developing a simple application which uses rand() frequently, and
I was just wondering if there are any alternatives to generating random
numbers other than the in-built function in C? I'm using GNU C/C++
compiler 3.3.1.

rand() works okay for me, but I suppose it has its limitations?

I have source for a portable C PRNG online at
http://benpfaff.org/writings/clc/random.html
You are welcome to use them if they solve your problem.

 

[Malcolm]

I'm developing a simple application which uses rand() frequently,
and I was just wondering if there are any alternatives to generating
random numbers other than the in-built function in C? I'm using
GNU C/C++ compiler 3.3.1.

rand() works okay for me, but I suppose it has its limitations.

There are many ways of generating random numbers. The main limitation of
rand() is that it uses a 32 bit seed, which means that a maximum of 4
billion numbers can be generated before it cycles.

This means that if, say, you are generating cards for a gambling game,
someone with access to your source code could write down the first ten or so
cards, match up the sequence, and determine the eleventh - on which maybe a
huge stake rests.

That said, the inbuilt rand() is ok for most purposes, but for a better RNG
look up "random number generator" on google. It might also be a good idea to
look in the cryptography newsgroups.