1 files changed, 37 insertions, 0 deletions
diff --git a/challenge-277/ulrich-rieke/cpp/ch-2.cpp b/challenge-277/ulrich-rieke/cpp/ch-2.cpp
new file mode 100755
index 0000000000..ec253a9451
--- /dev/null
+++ b/challenge-277/ulrich-rieke/cpp/ch-2.cpp
@@ -0,0 +1,37 @@
+#include <iostream>
+#include <iterator>
+#include <vector>
+#include <utility>
+#include <set>
+#include <algorithm>
+#include <cstdlib> // for abs
+#include <limits>  // for min
+
+bool condition( const std::pair<int , int> & p ) {
+   int diff = std::abs( p.first - p.second ) ;
+   int mini = std::min( p.first , p.second ) ;
+   return ( 0 < diff && ( diff < mini ) ) ;
+}
+
+int main( ) {
+   std::cout << "Enter some integers, separated by blanks!\n" ;
+   std::cout << "Enter e to end!\n" ;
+   std::vector<int> numbers { std::istream_iterator<int>( std::cin ) , 
+      std::istream_iterator<int>( ) } ;
+   std::vector<std::pair<int , int>> combinations , selected ;
+   int len = numbers.size( ) ;
+   for ( int i = 0 ; i < len - 1 ; i++ ) {
+      for ( int j = i + 1 ; j < len ; j++ ) {
+	 combinations.push_back( std::make_pair( numbers[i] , 
+		  numbers[j] )) ;
+      }
+   }
+   std::copy_if( combinations.begin( ) , combinations.end( ) , 
+	 std::back_inserter( selected ) , condition ) ;
+   //by creating a set from the vector selected that contains the pairs
+   //fulfilling the condition we remove duplicates
+   std::set<std::pair<int , int>> uniques ( selected.begin( ) , 
+	 selected.end( ) ) ;
+   std::cout << uniques.size( ) << '\n' ;
+   return 0 ;
+}