/* pi.c #2 */

#define pi "3.14159265358979323846264338327950288419716939937510"


#include <stdio.h>
#include <stdlib.h>
#include <math.h>

void sdiv(long num, long den, char *res, int prec);
void ssub(char *a, char *b, char *res);
int scomp(char *a, char *b);


main(int argc, char *argv[])
{
	long num,den;
	char acc[100],bacc[100],res[100];
	char *acc2;
	char tr;
	long cnt = 0;

	num=1;
	den=1;

	if (argc > 1) {
		num = atol(argv[1]);
		den = atol(argv[2]);
		if (den == 0) den = 1;
	}

	strcpy(bacc,"9.0000000000000000000000000000000000000000000");

	printf("<pre>pi = %-30s\n\n",pi);
	printf("%7s %7s = %-32s (%-23s)\n","Num.","Den.","Result","Accuracy");
	printf("%7s %7s = %-32s (%-23s)\n","-------","-------","----------------------","-----------------------");

	while (1) {
		sdiv(num,den,res,30);
		ssub(pi,res,acc);

/*		if (*kb & 1) cprintf("%7ld/%7ld = %.20s (%.20s)\r",num,den,res,acc);
*/
		if (acc[0] == '-') acc2 = acc+1;
			else acc2 = acc;

		tr = scomp(bacc,acc2);
		if (tr >= 0) {
/*			cprintf("%7ld/%7ld = %.20s (%.20s)",num,den,res,acc);
 */		if (tr == 0) {
				cnt++;
/*				cprintf(" (%d)\n\r",cnt);
 */		} else {
/*				cprintf("\n\r");
 */				if (cnt) printf(" (x %ld)",cnt+1);
				printf("\n%12ld/%12ld = %-30s (%33s)",num,den,res,acc);
				cnt = 0;
				for (cnt=0;acc2[cnt+2] == '0';cnt++);
				printf(" [%2d]",cnt);
				fflush(stdout);
				strcpy(bacc,acc2);
				cnt = 0;
			}
		}

		if (acc[0] == '-') {
			den+=1;
		} else {
			num+=1;
		}
	}
	printf("\n</pre>\n");
}


/*  ssub - subtracts two strings
 *   MUST BE DECIMAL ALIGNED!
 */

int ssub_borrow(char *a, char p)
{
	if (p == -1) return 0;
	if (a[p] == '.') {
		return ssub_borrow(a,p-1);
	} else if (a[p] == '0') {
		a[p] = '9';
		return ssub_borrow(a,p-1);
	} else {
		a[p]--;
	}
	return 1;
}

void ssub(char *a, char *b, char *res)
{
	int p;
	int rp;
	int tr;

	p = 0;
	rp = 0;

	while (a[p] && b[p]) {
		if (a[p] == '.') {
			res[rp++] = '.';
			p++;
		}
		tr = a[p] - b[p];
		if (tr < 0) {
			if (ssub_borrow(res,p-1)) {
				tr += 10;
			} else {
				res[0] = '-';
				ssub(b,a,res+1);
				return;
			}
		}
		res[rp++] = '0' + tr;
		p++;
	}
	res[rp] = 0;
}



/* scomp - compares two strings
 *   MUST BE DECIMAL ALIGNED!
 *  return 0 - a < b
 *  return 1 - a > b
 */

int scomp(char *a, char *b)
{
	int p;

	p = 0;

	while (a[p] && b[p]) {
		if (a[p] < b[p]) return -1;
		if (a[p] > b[p]) return 1;
		p++;
	}
	return 0;
}




/* sdiv - divide two ints - result put in a string
 *
 */

void sdiv(long num, long den, char *res, int prec)
{
	int p,pp;
	unsigned long car,ocar,t;
	int rp;

	char nums[20];
	char unums;

	sprintf(nums,"%ld",num);

	rp = 0;
	unums = 1;
	car = 0;
	p = 0;
	pp = 0;
	res[0] = 0;

	while (pp < prec) {
		car *= 10;
		if (unums) {
			if (nums[p]) {
				car += nums[p] - '0';
			} else {
				unums = 0;
				res[rp++] = '.';
				pp++;
			}
		} else pp++;
		ocar = car;
		t = car / den;
		if (t || res[0]) res[rp++] = '0' + t;
		t *= den;
		car = ocar - t;
		p++;
		if (car == 0 && unums == 0) break;
	}
	while (pp < prec) {
		res[rp++] = '0';
		pp++;
	}
	res[rp] = 0;
}


/*  		001
	234 | 2354908123
		  02
			0
			23
		  = 0
			235
			234
		  =  14


*/

/*


3.1297321
3.1278412
0.0018909

 3.1297321
 3.1278412
-0.001
*/