diff options
| author | Tobias Klauser <tklauser@distanz.ch> | 2008-01-27 11:37:44 +0100 |
|---|---|---|
| committer | Tobias Klauser <tklauser@xenon.tklauser.home> | 2008-01-27 11:37:44 +0100 |
| commit | 7e0f021a9aec35fd8e6725e87e3313b101d26f5e (patch) | |
| tree | b1cacc4b24393f517aeb4610e9e1021f954307a8 /reference/C/CONTRIB/SNIP/pi.c | |
Initial import (2.0.2-6)2.0.2-6
Diffstat (limited to 'reference/C/CONTRIB/SNIP/pi.c')
| -rwxr-xr-x | reference/C/CONTRIB/SNIP/pi.c | 155 |
1 files changed, 155 insertions, 0 deletions
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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