From 7e0f021a9aec35fd8e6725e87e3313b101d26f5e Mon Sep 17 00:00:00 2001
From: Tobias Klauser <tklauser@distanz.ch>
Date: Sun, 27 Jan 2008 11:37:44 +0100
Subject: Initial import (2.0.2-6)

---
 reference/C/CONTRIB/SNIP/pi.c | 155 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 155 insertions(+)
 create mode 100755 reference/C/CONTRIB/SNIP/pi.c

(limited to 'reference/C/CONTRIB/SNIP/pi.c')

diff --git a/reference/C/CONTRIB/SNIP/pi.c b/reference/C/CONTRIB/SNIP/pi.c
new file mode 100755
index 0000000..11c71f4
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/pi.c
@@ -0,0 +1,155 @@
+/*
+**  PI.C - Computes Pi to an arbitrary number of digits
+**
+**  Uses far arrays so may be compiled in any memory model
+*/
+
+#include<stdio.h>
+#include<stdlib.h>
+
+#if defined(__ZTC__)
+ #include <dos.h>
+ #define FAR _far
+ #define Fcalloc farcalloc
+ #define Ffree farfree
+ #define Size_T unsigned long
+#elif defined(__TURBOC__)
+ #include <alloc.h>
+ #define FAR far
+ #define Fcalloc farcalloc
+ #define Ffree farfree
+ #define Size_T unsigned long
+#else /* assume MSC/QC */
+ #include <malloc.h>
+ #define FAR _far
+ #define Fcalloc _fcalloc
+ #define Ffree _ffree
+ #define Size_T size_t
+#endif
+
+long kf, ks;
+long FAR *mf, FAR *ms;
+long cnt, n, temp, nd;
+long i;
+long col, col1;
+long loc, stor[21];
+
+void shift(long FAR *l1, long FAR *l2, long lp, long lmod)
+{
+      long k;
+
+      k = ((*l2) > 0 ? (*l2) / lmod: -(-(*l2) / lmod) - 1);
+      *l2 -= k * lmod;
+      *l1 += k * lp;
+}
+
+void yprint(long m)
+{
+      if (cnt<n)
+      {
+            if (++col == 11)
+            {
+                  col = 1;
+                  if (++col1 == 6)
+                  {
+                        col1 = 0;
+                        printf("\n");
+                        printf("%4ld",m%10);
+                  }
+                  else  printf("%3ld",m%10);
+            }
+            else  printf("%ld",m);
+            cnt++;
+      }
+}
+
+void xprint(long m)
+{
+      long ii, wk, wk1;
+
+      if (m < 8)
+      {
+            for (ii = 1; ii <= loc; )
+                  yprint(stor[(int)(ii++)]);
+            loc = 0;
+      }
+      else
+      {
+            if (m > 9)
+            {
+                  wk = m / 10;
+                  m %= 10;
+                  for (wk1 = loc; wk1 >= 1; wk1--)
+                  {
+                        wk += stor[(int)wk1];
+                        stor[(int)wk1] = wk % 10;
+                        wk /= 10;
+                  }
+            }
+      }
+      stor[(int)(++loc)] = m;
+}
+
+void memerr(int errno)
+{
+        printf("\a\nOut of memory error #%d\n", errno);
+        if (2 == errno)
+                Ffree(mf);
+        _exit(2);
+}
+
+int main(int argc, char *argv[])
+{
+      int i=0;
+      char *endp;
+
+      stor[i++] = 0;
+      if (argc < 2)
+      {
+            puts("\aUsage: PI <number_of_digits>");
+            return(1);
+      }
+      n = strtol(argv[1], &endp, 10);
+      if (NULL == (mf = Fcalloc((Size_T)(n + 3L), (Size_T)sizeof(long))))
+            memerr(1);
+      if (NULL == (ms = Fcalloc((Size_T)(n + 3L), (Size_T)sizeof(long))))
+            memerr(2);
+      printf("\nApproximation of PI to %ld digits\n", (long)n);
+      cnt = 0;
+      kf = 25;
+      ks = 57121L;
+      mf[1] = 1L;
+      for (i = 2; i <= (int)n; i += 2)
+      {
+            mf[i] = -16L;
+            mf[i+1] = 16L;
+      }
+      for (i = 1; i <= (int)n; i += 2)
+      {
+            ms[i] = -4L;
+            ms[i+1] = 4L;
+      }
+      printf("\n 3.");
+      while (cnt < n)
+      {
+            for (i = 0; ++i <= (int)n - (int)cnt; )
+            {
+                  mf[i] *= 10L;
+                  ms[i] *= 10L;
+            }
+            for (i =(int)(n - cnt + 1); --i >= 2; )
+            {
+                  temp = 2 * i - 1;
+                  shift(&mf[i - 1], &mf[i], temp - 2, temp * kf);
+                  shift(&ms[i - 1], &ms[i], temp - 2, temp * ks);
+            }
+            nd = 0;
+            shift((long FAR *)&nd, &mf[1], 1L, 5L);
+            shift((long FAR *)&nd, &ms[1], 1L, 239L);
+            xprint(nd);
+      }
+      printf("\n\nCalculations Completed!\n");
+      Ffree(ms);
+      Ffree(mf);
+      return(0);
+}
-- 
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