1 files changed, 67 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/OR_USING_C/03.2.c b/reference/C/CONTRIB/OR_USING_C/03.2.c
new file mode 100644
index 0000000..69d8904
--- /dev/null
+++ b/reference/C/CONTRIB/OR_USING_C/03.2.c
@@ -0,0 +1,67 @@
+/*
+ * If you're on System V, change <sys/file.h> to <sys/fcntl.h>.
+ */
+#include <sys/file.h>
+
+struct record {
+    int uid;
+    char login[9];
+};
+
+char *logins[] = { "user1", "user2", "user3",
+                   "user4", "user5" };
+
+main()
+{
+    int i, fd;
+    struct record rec;
+
+    /*
+     * Open the data file for writing.
+     */
+    if ((fd = open("datafile", O_WRONLY | O_CREAT, 0644)) < 0) {
+        perror("datafile");
+        exit(1);
+    }
+
+    /*
+     * For each user, going backwards...
+     */
+    for (i = 4; i >= 0; i--) {
+        /*
+         * Create the record.
+         */
+        rec.uid = i;
+        strcpy(rec.login, logins[i]);
+
+        /*
+         * Output the record.  Notice we pass the
+         * address of the structure.
+         */
+        putrec(fd, i, &rec);
+    }
+
+    close(fd);
+    exit(0);
+}
+
+/*
+ * putrec--write the record in the i'th position.
+ */
+putrec(fd, i, r)
+int i, fd;
+struct record *r;
+{
+    /*
+     * Seek to the i'th position from the beginning
+     * of the file.
+     */
+    lseek(fd, (long) i * sizeof(struct record), L_SET);
+
+    /*
+     * Write the record.  We want to write one
+     * object the size of a record structure.
+     */
+    write(fd, r, sizeof(struct record));
+}
+