1 files changed, 82 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/commafmt.c b/reference/C/CONTRIB/SNIP/commafmt.c
new file mode 100755
index 0000000..b5d24f7
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/commafmt.c
@@ -0,0 +1,82 @@
+/*
+**  COMMAFMT.C
+**
+**  Public domain by Bob Stout
+**
+**  Notes:  1. Use static buffer to eliminate error checks on buffer overflow
+**             and reduce code size.
+**          2. By making the numeric argument a long and prototyping it before
+**             use, passed numeric arguments will be implicitly cast to longs
+**             thereby avoiding int overflow.
+**          3. Use the thousands grouping and thousands separator from the
+**             ANSI locale to make this more robust.
+*/
+
+#include <string.h>
+#ifdef TEST
+ #include <stdlib.h>
+#endif
+
+#define NUL '\0'
+
+size_t commafmt(char   *buf,            /* Buffer for formatted string  */
+                int     bufsize,        /* Size of buffer               */
+                long    N)              /* Number to convert            */
+{
+        int len = 1, posn = 1, sign = 1;
+        char *ptr = buf + bufsize - 1;
+
+        if (2 > bufsize)
+        {
+ABORT:          *buf = NUL;
+                return 0;
+        }
+
+        *ptr-- = NUL;
+        --bufsize;
+        if (0L > N)
+        {
+                sign = -1;
+                N = -N;
+        }
+
+        for ( ; len <= bufsize; ++len, ++posn)
+        {
+                *ptr-- = (char)((N % 10L) + '0');
+                if (0L == (N /= 10L))
+                        break;
+                if (0 == (posn % 3))
+                {
+                        *ptr-- = ',';
+                        ++len;
+                }
+                if (len >= bufsize)
+                        goto ABORT;
+        }
+
+        if (0 > sign)
+        {
+                if (0 == bufsize)
+                        goto ABORT;
+                *ptr-- = '-';
+                ++len;
+        }
+
+        strcpy(buf, ++ptr);
+        return (size_t)len;
+}
+
+#ifdef TEST
+
+void main(int argc, char *argv[])
+{
+        size_t len;
+        char buf[20];
+        long N;
+
+        N = strtol(argv[1], NULL, 10);
+        len = commafmt(buf, 20, N);
+        printf("%s converts to %s and returned %d\n", argv[1], buf, len);
+}
+
+#endif