Create the generator polynomial g(x). g(x)=(x-a)(x-a^2)(x-a^3)..(x-a^N)

Multiply polynomial 'p1' to 'p2' and store the result in 'r'.

Safe append: resulting dest length cannot exceed maxlen and dest is always zero terminated. 'maxlen' parameter defines the entire dest buffer size and

Purely user interface function. Gets and returns user input.