/* ** PI.C - Computes Pi to an arbitrary number of digits ** ** Uses far arrays so may be compiled in any memory model */ #include #include #if defined(__ZTC__) #include #define FAR _far #define Fcalloc farcalloc #define Ffree farfree #define Size_T unsigned long #elif defined(__TURBOC__) #include #define FAR far #define Fcalloc farcalloc #define Ffree farfree #define Size_T unsigned long #else /* assume MSC/QC */ #include #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 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 "); 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); } 'left'>Commit message (Expand)AuthorFilesLines