Assignment Functions
--------------------

   These functions assign new values to already initialized integers
(see Initializing Integers.).

 - Function: void mpz_set (mpz_t ROP, mpz_t OP)
 - Function: void mpz_set_ui (mpz_t ROP, unsigned long int OP)
 - Function: void mpz_set_si (mpz_t ROP, signed long int OP)
 - Function: void mpz_set_d (mpz_t ROP, double OP)
 - Function: void mpz_set_q (mpz_t ROP, mpq_t OP)
 - Function: void mpz_set_f (mpz_t ROP, mpf_t OP)
     Set the value of ROP from OP.

 - Function: int mpz_set_str (mpz_t ROP, char *STR, int BASE)
     Set the value of ROP from STR, a '\0'-terminated C string in base
     BASE.  White space is allowed in the string, and is simply
     ignored.  The base may vary from 2 to 36.  If BASE is 0, the
     actual base is determined from the leading characters: if the
     first two characters are `0x' or `0X', hexadecimal is assumed,
     otherwise if the first character is `0', octal is assumed,
     otherwise decimal is assumed.

     This function returns 0 if the entire string up to the '\0' is a
     valid number in base BASE.  Otherwise it returns -1.