Maarten Kronenburg wrote:
In my opinion the unsigned integer with a modulus is required, which is generalizing the base type unsigned int (which is modular) to any modulus. So the unsigned_integer would have a static method void set_modulus( const integer & ). The only problem is what an unsigned_integer is when a modulus is not providid, that is when the modulus is zero. Then I propose that as the user did not provide any modulus, only in this case negating a non-zero unsigned_integer will be an error. Also I propose that such an unsigned_integer will be provided by implementations, and be added to the specification.
Or you drop unsigned_integer completely (David convinced me that it is not really needed) and only have a modulus version, which takes the modulus as a constructor argument. Then negation is always defined. Sebastian Redl