/****************************************************

A BigInt is held in a form of binary-coded decimal, in an array of
unsigned long long elements
ANSI requires an unsigned long long to be at least 18 X 10^18
We hold 0 to 10^9-1 ( 9 decimal digits) in each element
Then an intermediate product of the two = 10^18 will also fit into an unsigned long long

The sign is held in the 'sign' field as a char, + or -

The array is 1024 long, so we can handle up to 9216 decimal digits.

For bigger than this (!) the 'next' field points to another BigInt, as a linked list - so
that there is no limit to the size of a number other than total memory.

This format is designed to be able to use processor instructions to do arithmetic in 10^9 size chunks.


*****************************************************/

struct BIStruct
{
char sign;                          // + or -
unsigned long long digits[1024];    // The digits, in 10^9 chunks
int listCount;                      // 0,1,2.. through the linked list
struct BIStruct * next;             // pointer to next block
int elementCount;                   // array elements 0 to elementCount-1 are non-garbage
};

typedef struct BIStruct BigInt;