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/* Copyright (C) 1991 1995 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
* As a special exception, the Free Software Foundation gives permission
* for additional uses of the text contained in its release of GUILE.
*
* The exception is that, if you link the GUILE library with other files
* to produce an executable, this does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* Your use of that executable is in no way restricted on account of
* linking the GUILE library code into it.
*
* This exception does not however invalidate any other reasons why
* the executable file might be covered by the GNU General Public License.
*
* This exception applies only to the code released by the
* Free Software Foundation under the name GUILE. If you copy
* code from other Free Software Foundation releases into a copy of
* GUILE, as the General Public License permits, the exception does
* not apply to the code that you add in this way. To avoid misleading
* anyone as to the status of such modified files, you must delete
* this exception notice from them.
*
* If you write modifications of your own for GUILE, it is your choice
* whether to permit this exception to apply to your modifications.
* If you do not wish that, delete this exception notice.
*/
/* "pi.c", program for computing digits of numerical value of PI.
Author: Aubrey Jaffer
pi <n> <d> prints out <n> digits of pi in groups of <d> digits.
'Spigot' algorithm origionally due to Stanly Rabinowitz.
This algorithm takes time proportional to the square of <n>/<d>.
This fact can make comparisons of computational speed between systems
of vastly differring performances quicker and more accurate.
Try: pi 100 5
The digit size <d> will have to be reduced for larger <n> or an
error due to overflow will occur. */
short *calloc();
main(c,v)
int c;char **v;{
int n=200,j=0,m,b=2,k=0,t,r=1,d=5;
long q;
short *a;
if(c>1)n=atoi(v[1]);
if(c>2)d=atoi(v[2]);
while(k++<d)r=r*10;
n=n/d+1;
k=m=3.322*n*d;
a=calloc(1+m,2);
while(k)a[--k]=2;
for(a[m]=4;j<n;b=q%r){
q=0;
for(k=m;k;){
q+=a[k]*r;
t=(2*k+1);
a[k]=q%t;
q=q/t;
q*=k--;}
printf("%0*d%s",d,b+q/r,++j%10?" ":"\n");}
puts("");}
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