// BigNumber example: Calculate decimal digits of Pi using Gosper's series
// http://www.cs.ox.ac.uk/people/jeremy.gibbons/publications/spigot.pdf

// #include <BigNumber.h>       // For a normal Arduino project
#include "BigNumber.h"          // For Wokwi simulation

// constants
const BigNumber one(1);
const BigNumber two(2);
const BigNumber three(3);
const BigNumber five(5);
const BigNumber ten(10);
const BigNumber twelve(12);
const BigNumber twentyseven(27);

// variables
BigNumber q(1);
BigNumber r(180);
BigNumber t(60);
BigNumber i(2);
BigNumber u, y;

void setup() {
  Serial1.begin(115200);
  BigNumber::begin(0);  // everything is integers throughout
}

void loop() {
  // Gibbons' spigot
  u = three * (three * i + one) * (three * i + two);
  y = (q * (twentyseven * i - twelve) + five * r) / (five * t);
  r = ten * u * (q * (five * i - two) + r - y * t);
  q = ten * q * i * (two * i - one);
  t *= u;
  Serial1.print(y);
  if (i++ == 2)
    Serial1.print('.');
}