Or, if you are masochistic, add a binding of a big number library to gsc:
https://gmplib.org/
Code:
gcc -o add_example add_example.c -lgmp -lm
Code:
#include <stdio.h> /* for printf */
#include <gmp.h>
int main(int argc, char *argv[])
{
mpz_t a, b; /* working numbers */
if (argc<3)
{ /* not enough words */
printf("Please supply two numbers to add.\n");
return 1;
}
mpz_init_set_str (a, argv[1], 10); /* Assume decimal integers */
mpz_init_set_str (b, argv[2], 10); /* Assume decimal integers */
mpz_add (a, a, b); /* a=a+b */
printf("%s + %s => %s\n", argv[1], argv[2], mpz_get_str (NULL, 10, a));
return 0;
}