diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1661636
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+CMakeLists.txt.user
+
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 577503a..840802f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,6 +13,20 @@ else()
     message("doxygen not found")
 endif()
 
+##############################################################################
+# C++11 support
+##############################################################################
+include(CheckCXXCompilerFlag)
+CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)
+CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPILER_SUPPORTS_CXX0X)
+if(COMPILER_SUPPORTS_CXX11)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
+elseif(COMPILER_SUPPORTS_CXX0X)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
+else()
+    message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Some functionality will not be available.")
+endif()
+
 ##############################################################################
 # MSVC-specific settings
 ##############################################################################
diff --git a/include/andres/marray.hxx b/include/andres/marray.hxx
index 229ec3d..44ef0b1 100644
--- a/include/andres/marray.hxx
+++ b/include/andres/marray.hxx
@@ -79,6 +79,7 @@
 #define MARRAY_HXX
 
 #include <cassert>
+#include <cstddef>
 #include <stdexcept> // runtime_error
 #include <limits>
 #include <string>
diff --git a/include/andres/ml/decision-trees.hxx b/include/andres/ml/decision-trees.hxx
index 7c8d8d9..eb6b94c 100644
--- a/include/andres/ml/decision-trees.hxx
+++ b/include/andres/ml/decision-trees.hxx
@@ -786,7 +786,8 @@ DecisionForest<FEATURE, LABEL, PROBABILITY>::learn(
     const size_t numberOfDecisionTrees
 ) {
     typedef std::default_random_engine RandomEngine;
-    learn<RandomEngine>(features, labels, numberOfDecisionTrees, RandomEngine());
+    RandomEngine randomEngine;
+    learn<RandomEngine>(features, labels, numberOfDecisionTrees, randomEngine);
 }
 
 /// Learns a decision forest from labeled samples as described by Breiman (2001).
diff --git a/src/unittest/ml/test-decision-trees.cxx b/src/unittest/ml/test-decision-trees.cxx
index 4157583..8363a4c 100644
--- a/src/unittest/ml/test-decision-trees.cxx
+++ b/src/unittest/ml/test-decision-trees.cxx
@@ -16,7 +16,7 @@ int main() {
     // define random feature matrix
     std::default_random_engine RandomNumberGenerator;
     typedef double Feature;
-    std::uniform_int_distribution<double> randomDistribution(0.0, 1.0);
+    std::uniform_real_distribution<double> randomDistribution(0.0, 1.0);
     const size_t shape[] = {numberOfSamples, numberOfFeatures};
     andres::Marray<Feature> features(shape, shape + 2);
     for(size_t sample = 0; sample < numberOfSamples; ++sample)