Arithmetics for pie and e

[Yok]

somebody please give me Arithmetics for pie and e,both in C or Basic is OK

[jim mcnamara]

ArcTan method for pi in C

****************************************/
/* Compute pi to arbitrary precision */
/* Author Roy Williams February 1994 */
/* roy@ccsf.caltech.edu */
/* Uses Machin's formula... */
/* pi/4 = 4 arctan(1/5) - arctan(1/239) */
/****************************************/
/* compile with cc -O -o pi1 pi1.c */
/* run as "pi 1000" for 1000 digits */
/****************************************/
/* The last few digits may be wrong.......... */

#include <stdio.h>

#define BASE 10000
int nblock;
int *tot;
int *t1;
int *t2;
int *t3;

main(argc, argv)
int argc;
char **argv;
{
int ndigit = 60;
if(argc == 2)
ndigit = atoi(argv[1]);
else {
fprintf(stderr, "Usage: %s ndigit\n", argv[0]);
fprintf(stderr, "(Assuming 60 digits)\n");
}
if(ndigit < 20) ndigit = 20;
nblock = ndigit/4;
tot = (int *)malloc(nblock*sizeof(int));
t1 = (int *)malloc(nblock*sizeof(int));
t2 = (int *)malloc(nblock*sizeof(int));
t3 = (int *)malloc(nblock*sizeof(int));
if(!tot || !t1 || !t2 || !t3){
fprintf(stderr, "Not enough memory\n");
exit(1);
}

arctan(tot, t1, t2, 5, 1);
mult(tot, 4);
arctan(t3, t1, t2, 239, 2);
sub(tot, t3);
mult(tot, 4);
print(tot);
}

arctan(result, w1, w2, denom, onestep)
int *result, *w1, *w2, denom, onestep;
{
int denom2 = denom*denom;
int k = 1;

set(result, 1);
div(result, denom);
copy(w1, result);

do{
if(onestep)
div(w1, denom2);
else {
div(w1, denom);
div(w1, denom);
}
copy(w2, w1);
div(w2, 2*k+1);
if(k%2)
sub(result, w2);
else
add(result, w2);
k++;
} while(!zero(w2));
}

copy(result, from)
int *result, *from;
{
int i;
for(i=0; i<nblock; i++)
result[i] = from[i];
}

zero(result)
int *result;
{
int i;
for(i=0; i<nblock; i++)
if(result[i])
return 0;
return 1;
}

add(result, increm)
int *result, *increm;
{
int i;
for(i=nblock-1; i>=0; i--){
result[i] += increm[i];
if(result[i] >= BASE){
result[i] -= BASE;
result[i-1]++;
}
}
}

sub(result, decrem)
int *result, *decrem;
{
int i;
for(i=nblock-1; i>=0; i--){
result[i] -= decrem[i];
if(result[i] < 0){
result[i] += BASE;
result[i-1]--;
}
}
}

mult(result, factor)
int *result, factor;
{
int i, carry = 0;
for(i=nblock-1; i>=0; i--){
result[i] *= factor;
result[i] += carry;
carry = result[i]/BASE;
result[i] %= BASE;
}
}

div(result, denom)
int *result, denom;
{
int i, carry = 0;

for(i=0; i<nblock; i++){
result[i] += carry*BASE;
carry = result[i] % denom;
result[i] /= denom;
}
}

set(result, rhs)
int *result, rhs;
{
int i;
for(i=0; i<nblock; i++)
result[i] = 0;
result[0] = rhs;
}

print(result)
int *result;
{
int i, k;
char s[10];
printf("%1d.\n", result[0]);
for(i=1; i<nblock; i++){
sprintf(s, "%4d ", result[i]);
for(k=0; k<5; k++)
if(s[k] == ' ') s[k] = '0';
printf("%c%c%c%c", s[0], s[1], s[2], s[3]);
if(i%15 == 0) printf("\n");
}
printf("\n");
}

[transcendental]

Looks like Unix C to me.

[jim mcnamara]

It's vanilla C and will compile under VC++ if you save it as
filename.c instead of filename.cpp

You can compile it with

cl filename.c

It will run in an MS-DOS window.

BTW, there is no such thing as "UNIX C" - and I oughta know. Ive coding C on various boxes (MS-DOS, VMS, UNIX) for .... years.
Very many years.

There is ANSI C, POSIX compliant C, C89 (ANSI) and C99 (ANSI), to name a few. Even Turbo C( back in the 80's) was ansi-compliant - ie., you could port it to VMS or UNIX.

[Yok]

Can you give me the remark of your sourcecode,jim?Thank u

[jim mcnamara]

I'm not sure what you mean by 'remark of sourcecode'

The code is ansi-c - you can compile it and use it as you see fit.
I got it several years ago at a meeting, R Williams gets the credit for the code, not me.