1 files changed, 50 insertions, 0 deletions
diff --git a/challenge-336/ulrich-rieke/cpp/ch-2.cpp b/challenge-336/ulrich-rieke/cpp/ch-2.cpp
new file mode 100755
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+++ b/challenge-336/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,50 @@
+#include <vector>
+#include <string>
+#include <sstream>
+#include <regex>
+#include <iostream>
+#include <numeric>
+#include <algorithm>
+
+std::vector<std::string> split( const std::string & text , char delimiter ) {
+   std::vector<std::string> tokens ;
+   std::istringstream istr { text } ;
+   std::string word ;
+   while ( std::getline( istr , word , delimiter ) ) 
+      tokens.push_back( word ) ;
+   return tokens ;
+}
+
+int main( ) {
+   std::cout << "Enter some numbers and D , C or + separated by whitespace!\n" ;
+   std::string line ;
+   std::getline( std::cin , line ) ;
+   auto tokens { split( line , ' ' ) } ;
+   std::vector<int> numbers ;
+   std::string numpattern {"(\\-)*\\d+"} ;
+   std::regex nu { numpattern } ;
+   auto until = std::find_if( tokens.begin( ) , tokens.end( ) , [nu]( const auto w )
+	 { return ! std::regex_match( w.begin( ) , w.end( ) , nu ) ; } ) ;
+   for ( auto it = tokens.begin( ) ; it != until ; ++it ) 
+      numbers.push_back( std::stoi( *it ) ) ;
+   for ( auto it = until ; it != tokens.end( ) ; ++it ) {
+      if ( ! std::regex_match( *it , nu ) ) { // no number ! 
+	 if ( *it == "C" ) {
+	    numbers.pop_back( ) ;
+	 }
+	 if ( *it == "D" ) {
+	    int last = numbers.back( ) ;
+	    numbers.push_back( last * 2 ) ;
+	 }
+	 if ( *it == "+" ) {
+	    int l = numbers.size( ) ;
+	    numbers.push_back( numbers[l - 2] + numbers[l - 1] ) ;
+	 }
+      }
+      else { // it's a number !
+	 numbers.push_back( std::stoi( *it ) ) ;
+      }
+   }
+   std::cout << std::accumulate( numbers.begin( ) , numbers.end( ) , 0 ) << '\n' ;
+   return 0 ;
+}