1 files changed, 35 insertions, 0 deletions
diff --git a/challenge-159/ulrich-rieke/cpp/ch-1.cpp b/challenge-159/ulrich-rieke/cpp/ch-1.cpp
new file mode 100644
index 0000000000..fd619c7af4
--- /dev/null
+++ b/challenge-159/ulrich-rieke/cpp/ch-1.cpp
@@ -0,0 +1,35 @@
+#include <vector>
+#include <iostream>
+#include <numeric>
+#include <utility>
+#include <cstdlib>
+#include <algorithm>
+
+int main( int argc, char * argv[] ) {
+  int n = std::atoi( argv[1] ) ;
+  while ( n <= 0 ) {
+      std::cout << "Please enter an integer greater than 0!\n" ;
+      std::cin >> n ;
+  }
+  std::vector<int> numerators( n  ) ;
+  std::vector<int> denominators( n + 1 ) ;
+  std::iota( numerators.begin( ) , numerators.end( ) , 1) ;
+  std::iota( denominators.begin( ) , denominators.end( ) , 0 ) ;
+  std::vector<std::pair<int, int>> fractions ;
+  fractions.push_back( std::make_pair( 0 , 1 ) ) ;
+  for ( int i : numerators ) {
+      for ( int j : denominators ) {
+    if ( i < j && (std::lcm( i , j ) == i * j)) {
+        fractions.push_back( std::make_pair( i , j )) ;
+    }
+      }
+  }
+  std::sort( fractions.begin( ) , fractions.end( ) ,
+    []( const auto & a, const auto & b ) { return
+    (static_cast<double>(a.first) / static_cast<double>(a.second)) <
+    (static_cast<double>(b.first) / static_cast<double>(b.second));} );
+  for ( auto & p : fractions )
+      std::cout << p.first << '/' << p.second << ", " ;
+  std::cout << "1/1" << std::endl ;
+  return 0 ;
+}