Add conversion_use_case

example/conversion_use_case.cpp

@@ -0,0 +1,51 @@
+//  endian/example/conversion_use_case.cpp 
+
+//  Copyright Beman Dawes 2014
+
+//  Distributed under the Boost Software License, Version 1.0.
+//  See http://www.boost.org/LICENSE_1_0.txt
+
+//  This program reads a binary file of fixed length records, with a format defined
+//  in a header file supplied by a third-party. The records inserted into a vector,
+//  and the vector is sorted. The sorted records are then written to an output file.
+
+//  Full I/O error testing omitted for brevity, So don't try this at home.
+
+#include "third_party_format.hpp"
+#include <boost/endian/conversion.hpp>
+#include <vector>
+#include <fstream>
+#include <algorithm>
+#include <iostream>
+
+using third_party::record;
+
+int main()
+{
+  std::ifstream in("data.bin", std::ios::binary);
+  if (!in) { std::cout << "Could not open data.bin\n"; return 1; }
+
+  std::ofstream out("sorted-data.bin", std::ios::binary);
+  if (!out) { std::cout << "Could not open sorted-data.bin\n"; return 1; }
+
+  record rec;
+  std::vector<record> recs;
+
+  while (!in.eof())  // read each record
+  {
+    in.read((char*)&rec, sizeof(rec));
+    rec.balance = boost::endian::big_to_native(rec.balance);  // reverse if needed
+    recs.push_back(rec);
+  }
+
+  std::sort(recs.begin(), recs.end(),  // decending sort by balance
+    [](const record& lhs, const record& rhs) -> bool
+      { return lhs.balance > rhs.balance; });
+
+  for (auto &out_rec : recs)  // write each record
+  {
+    out_rec.balance = boost::endian::native_to_big(rec.balance);  // reverse if needed
+    out.write((const char*)&out_rec, sizeof(out_rec));
+  }
+    
+}