Add a -d flag so that primes will print the difference between the current

[bsdgames-darwin.git] / primes / primes.c

diff --git a/primes/primes.c b/primes/primes.c
index dd29545a34d605d725adbdb0df1622167dbe2f05..a93e7110270ba7435cf3c770bba996db9688bc68 100644 (file)
--- a/primes/primes.c
+++ b/primes/primes.c
@@ -1,4 +1,4 @@
-/*     $NetBSD: primes.c,v 1.14 2008/02/02 17:45:05 matt Exp $ */
+/*     $NetBSD: primes.c,v 1.15 2008/02/02 18:15:14 matt Exp $ */
 
 /*
  * Copyright (c) 1989, 1993
@@ -42,7 +42,7 @@ __COPYRIGHT("@(#) Copyright (c) 1989, 1993\n\
 #if 0
 static char sccsid[] = "@(#)primes.c   8.5 (Berkeley) 5/10/95";
 #else
-__RCSID("$NetBSD: primes.c,v 1.14 2008/02/02 17:45:05 matt Exp $");
+__RCSID("$NetBSD: primes.c,v 1.15 2008/02/02 18:15:14 matt Exp $");
 #endif
 #endif /* not lint */
 
@@ -103,23 +103,26 @@ extern const ubig *pr_limit;              /* largest prime in the prime array */
 extern const char pattern[];
 extern const int pattern_size; /* length of pattern array */
 
+int    dflag;
+
 int    main(int, char *[]);
 void   primes(ubig, ubig);
 ubig   read_num_buf(void);
 void   usage(void) __dead;
 
 int
-main(argc, argv)
-       int argc;
-       char *argv[];
+main(int argc, char *argv[])
 {
        ubig start;             /* where to start generating */
        ubig stop;              /* don't generate at or above this value */
        int ch;
        char *p;
 
-       while ((ch = getopt(argc, argv, "")) != -1)
+       while ((ch = getopt(argc, argv, "d")) != -1)
                switch (ch) {
+               case 'd':
+                       dflag++;
+                       break;
                case '?':
                default:
                        usage();
@@ -186,7 +189,7 @@ main(argc, argv)
  *     This routine returns a number n, where 0 <= n && n <= BIG.
  */
 ubig
-read_num_buf()
+read_num_buf(void)
 {
        ubig val;
        char *p, buf[100];              /* > max number of digits. */
@@ -214,11 +217,12 @@ read_num_buf()
 
 /*
  * primes - sieve and print primes from start up to and but not including stop
+ *
+ *     start   where to start generating
+ *     stop    don't generate at or above this value
  */
 void
-primes(start, stop)
-       ubig start;     /* where to start generating */
-       ubig stop;      /* don't generate at or above this value */
+primes(ubig start, ubig stop)
 {
        char *q;                /* sieve spot */
        ubig factor;            /* index and factor */
@@ -226,6 +230,7 @@ primes(start, stop)
        const ubig *p;          /* prime table pointer */
        ubig fact_lim;          /* highest prime for current block */
        ubig mod;               /* temp storage for mod */
+       ubig prev = 0;
 
        /*
         * A number of systems can not convert double values into unsigned
@@ -260,8 +265,14 @@ primes(start, stop)
                for (p = &prime[0], factor = prime[0];
                    factor < stop && p <= pr_limit; factor = *(++p)) {
                        if (factor >= start) {
-                               printf("%lu\n", (unsigned long) factor);
+                               printf("%lu", (unsigned long) factor);
+                               if (dflag) {
+                                       printf(" (%lu)",
+                                           (unsigned long) factor - prev);
+                               }
+                               putchar('\n');
                        }
+                       prev = factor;
                }
                /* return early if we are done */
                if (p <= pr_limit) {
@@ -323,15 +334,21 @@ primes(start, stop)
                 */
                for (q = table; q < tab_lim; ++q, start+=2) {
                        if (*q) {
-                               printf("%lu\n", (unsigned long) start);
+                               printf("%lu", (unsigned long) start);
+                               if (dflag) {
+                                       printf(" (%lu)",
+                                           (unsigned long) start - prev);
+                                       prev = start;
+                               }
+                               putchar('\n');
                        }
                }
        }
 }
 
 void
-usage()
+usage(void)
 {
-       (void)fprintf(stderr, "usage: primes [start [stop]]\n");
+       (void)fprintf(stderr, "usage: primes [-d] [start [stop]]\n");
        exit(1);
 }