Add decNumber library

The library adds support for decimal numbers of arbitrary length.
Downloaded from ICU, under ICU 1.8.1 license
http://download.icu-project.org/files/decNumber/decNumber-icu-368.zip

src/decNumber/example1.c

@@ -0,0 +1,38 @@
+/* ------------------------------------------------------------------ */
+/* Decimal Number Library Demonstration program                       */
+/* ------------------------------------------------------------------ */
+/* Copyright (c) IBM Corporation, 2001, 2007.  All rights reserved.   */
+/* ----------------------------------------------------------------+- */
+/*                                                 right margin -->|  */
+
+// example1.c -- convert the first two argument words to decNumber,
+// add them together, and display the result
+
+#define  DECNUMDIGITS 34           // work with up to 34 digits
+#include "decNumber.h"             // base number library
+#include <stdio.h>                 // for printf
+
+int main(int argc, char *argv[]) {
+  decNumber a, b;                  // working numbers
+  decContext set;                  // working context
+  char string[DECNUMDIGITS+14];    // conversion buffer
+
+  decContextTestEndian(0);         // warn if DECLITEND is wrong
+
+  if (argc<3) {                    // not enough words
+    printf("Please supply two numbers to add.\n");
+    return 1;
+    }
+  decContextDefault(&set, DEC_INIT_BASE); // initialize
+  set.traps=0;                     // no traps, thank you
+  set.digits=DECNUMDIGITS;         // set precision
+
+  decNumberFromString(&a, argv[1], &set);
+  decNumberFromString(&b, argv[2], &set);
+
+  decNumberAdd(&a, &a, &b, &set);            // a=a+b
+  decNumberToString(&a, string);
+
+  printf("%s + %s => %s\n", argv[1], argv[2], string);
+  return 0;
+  } // main