Looking for large integer routines...help? :-)

[Jacob Ben-david Zimmerman]

Hi world.  I am a very very very new C programmer, and I find myself in
need of some routines which I am attempting to puzzle out without much
luck. If anyone can & is willing to help me out, please reply.  Thanks!
I am in need of routines to do the following:
-create large (~100-200 digit) integers (random ones.)
-check if they are prime or not
-->OR simply create large (~100-200 digit) prime numbers.
-multiply and divide them with modulus.

I am learning to use ANSI C.  Any pointers appreciated.  Thanks!

-JBZimmerman!
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