#9 correct (c) and add find_nth

StringUtils.cpp

@@ -0,0 +1,35 @@
+/*
+ *   Copyright (c) 2021-2022 by Geoffrey Merck F4FXL / KC3FRA
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "StringUtils.h"
+
+size_t CStringUtils::find_nth(const std::string& haystack, size_t pos, char needle, size_t nth) 
+{
+    size_t matches = 0U;
+    auto haystackLength = haystack.length();
+
+    for(size_t i = 0; i < haystackLength; i++) {
+        if(haystack[i] == needle) {
+            matches++;
+            if(matches == nth)
+                return i;
+        }
+    }
+
+    return std::string::npos;
+}

StringUtils.h

@@ -1,7 +1,5 @@
 /*
- *   Copyright (C) 2009-2011,2013 by Jonathan Naylor G4KLX
- *   Copyright (c) 2017 by Thomas A. Early N7TAE
- *   Copyright (c) 2021 by Geoffrey Merck F4FXL / KC3FRA
+ *   Copyright (c) 2021-2022 by Geoffrey Merck F4FXL / KC3FRA
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -38,4 +36,6 @@ public:
         std::snprintf( buf.get(), size, format.c_str(), args ... );
         return std::string( buf.get(), buf.get() + size - 1 ); // We don't want the '\0' inside
     }
+
+    static size_t find_nth(const std::string& haystack, size_t pos, char needle, size_t nth);
 };