STYLE: Use range-based loops from C++11

Used as a more readable equivalent to the traditional for loop operating
over a range of values, such as all elements in a container, in the
forward direction.

====
Range based loopes are more explicit for only computing the
end location once for containers.

for ( ImageIORegion::IndexType::const_iterator i = this->GetIndex().begin();
  i != this->GetIndex().end(); //<- NOTE: Compute end every loop iteration
  ++i )

for (long i : this->GetIndex()) //<- NOTE: Implicitly only compute end once

====
Explicitly reduce the amount of index computations: (The compiler
probably does this too)

for(int i = 0; i < 11; i++)
  {
  pos[0] = testPoints[i][0];
  pos[1] = testPoints[i][1];
                    ^^^^

for(auto & testPoint : testPoints)
  {
  pos[0] = testPoint[0];
  pos[1] = testPoint[1];

====

SRCDIR=/Users/johnsonhj/Dashboard/src/ITK #My local SRC
BLDDIR=/Users/johnsonhj/Dashboard/src/ITK-clangtidy/ #My local BLD

cd /Users/johnsonhj/Dashboard/src/ITK-clangtidy/
run-clang-tidy.py -checks=-*,modernize-loop-convert  -header-filter=.* -fix

Change-Id: I9a6b6a73491beb61fde913e3a2cf209f7c8601e5

Author: hjmjohnson

Examples/Filtering/BilateralImageFilter.cxx

@@ -181,9 +181,9 @@ int main( int argc, char * argv[] )
   // Software Guide : BeginCodeSnippet
   const unsigned int Dimension = InputImageType::ImageDimension;
   double domainSigmas[ Dimension ];
-  for(unsigned int i=0; i<Dimension; i++)
+  for(double & domainSigma : domainSigmas)
     {
-    domainSigmas[i] = atof( argv[3] );
+    domainSigma = atof( argv[3] );
     }
   const double rangeSigma = atof( argv[4] );
   // Software Guide : EndCodeSnippet

Examples/IO/IOFactoryRegistration.cxx

@@ -23,19 +23,17 @@
 // corresponding IO factory will be automatically registered.
 int main()
 {
-  std::list<itk::ObjectFactoryBase *> factories =
+  const std::list<itk::ObjectFactoryBase *> & factories =
     itk::ObjectFactoryBase::GetRegisteredFactories();
   const std::size_t numFactories = factories.size();
 
   std::cout << numFactories << " Image IO factories registered:" << std::endl;
 
   if (!factories.empty() )
     {
-    for ( std::list<itk::ObjectFactoryBase*>::iterator
-          f = factories.begin();
-          f != factories.end(); ++f )
+    for (const auto & factory : factories)
       {
-      std::istringstream iss( (*f)->GetDescription() );
+      std::istringstream iss( factory->GetDescription() );
       std::string        IOType;
       iss >> IOType; // the first word of the description
       std::cout << IOType << " ";

Examples/IO/IOPlugin.cxx

@@ -61,20 +61,18 @@ int main( int argc, char *argv[] )
   std::cout << "Count: " << numFactories << std::endl;
   if (!factories.empty())
     {
-    for ( std::list<itk::ObjectFactoryBase*>::iterator
-            f = factories.begin();
-          f != factories.end(); ++f )
+    for (auto & factory : factories)
       {
       std::cout << "  Factory version: "
-                << (*f)->GetITKSourceVersion() << std::endl
+                << factory->GetITKSourceVersion() << std::endl
                 << "  Factory description: "
-                << (*f)->GetDescription() << std::endl
-                << "  Library Path: " << (*f)->GetLibraryPath() << std::endl;
+                << factory->GetDescription() << std::endl
+                << "  Library Path: " << factory->GetLibraryPath() << std::endl;
 
-      std::list<std::string> overrides = (*f)->GetClassOverrideNames();
-      std::list<std::string> names = (*f)->GetClassOverrideWithNames();
-      std::list<std::string> descriptions = (*f)->GetClassOverrideDescriptions();
-      std::list<bool> enableflags = (*f)->GetEnableFlags();
+      std::list<std::string> overrides = factory->GetClassOverrideNames();
+      std::list<std::string> names = factory->GetClassOverrideWithNames();
+      std::list<std::string> descriptions = factory->GetClassOverrideDescriptions();
+      std::list<bool> enableflags = factory->GetEnableFlags();
       std::list<std::string>::const_iterator n = names.begin();
       std::list<std::string>::const_iterator d = descriptions.begin();
       std::list<bool>::const_iterator e = enableflags.begin();
@@ -144,23 +142,21 @@ int main( int argc, char *argv[] )
 
   if (!factories.empty())
     {
-    for ( std::list<itk::ObjectFactoryBase*>::iterator
-            f = factories.begin();
-          f != factories.end(); ++f )
+    for (auto & factory : factories)
       {
-      std::cout << "check " << (void *) *f << std::endl;
+      std::cout << "check " << (void *) factory << std::endl;
       std::cout << "  Factory version: "
-                << (*f)->GetITKSourceVersion() << std::endl
+                << factory->GetITKSourceVersion() << std::endl
                 << "  Factory description: "
-                << (*f)->GetDescription() << std::endl;
+                << factory->GetDescription() << std::endl;
 
-      std::list<std::string> overrides = (*f)->GetClassOverrideNames();
+      std::list<std::string> overrides = factory->GetClassOverrideNames();
       std::cout << "ClassOverrideNames size: " << overrides.size() << std::endl;
-      std::list<std::string> names = (*f)->GetClassOverrideWithNames();
+      std::list<std::string> names = factory->GetClassOverrideWithNames();
       std::cout << "ClassOverrideWithNames size: " << names.size() << std::endl;
-      std::list<std::string> descriptions = (*f)->GetClassOverrideDescriptions();
+      std::list<std::string> descriptions = factory->GetClassOverrideDescriptions();
       std::cout << "ClassOverrideDescriptions size: " << descriptions.size() << std::endl;
-      std::list<bool> enableflags = (*f)->GetEnableFlags();
+      std::list<bool> enableflags = factory->GetEnableFlags();
       std::cout << "EnableFlags size: " << enableflags.size() << std::endl;
       std::list<std::string>::const_iterator n = names.begin();
       std::list<std::string>::const_iterator d = descriptions.begin();

Examples/IO/XML/itkParticleSwarmOptimizerDOMWriter.cxx

@@ -68,11 +68,10 @@ ParticleSwarmOptimizerDOMWriter::GenerateData( DOMNodeType* outputdom, const voi
 
   std::vector<double> lbound;
   std::vector<double> ubound;
-  ParticleSwarmOptimizer::ParameterBoundsType bounds = ipobj->GetParameterBounds();
-  for ( size_t i = 0; i < bounds.size(); i++ )
+  for (auto & bound : ipobj->GetParameterBounds() )
     {
-    lbound.push_back( bounds[i].first );
-    ubound.push_back( bounds[i].second );
+    lbound.push_back( bound.first );
+    ubound.push_back( bound.second );
     }
   // generate and insert the DOM node for the lower bound of the parameters
   logger->Info( "writing LowerBound ...\n" );

Examples/IO/XML/itkParticleSwarmOptimizerSAXReader.cxx

@@ -274,9 +274,9 @@ const char* ParticleSwarmOptimizerSAXReader::GetAttribute( const char** atts, co
 bool ParticleSwarmOptimizerSAXReader::ContextIs( const char* test ) const
 {
   std::string s = "";
-  for ( size_t i = 0; i < this->m_CurrentTags.size(); i++ )
+  for (const auto currentTag : this->m_CurrentTags)
     {
-    s += "/" + std::string(this->m_CurrentTags[i]);
+    s += "/" + std::string(currentTag);
     }
   if ( s.size() == 0 )
     {

Examples/IO/XML/itkParticleSwarmOptimizerSAXWriter.cxx

@@ -82,17 +82,13 @@ int ParticleSwarmOptimizerSAXWriter::WriteFile()
     ofs << ">";
     ofs << "\n";
 
-    //
-    ParticleSwarmOptimizer::ParameterBoundsType bounds = this->m_InputObject->GetParameterBounds();
-
     // write the lower bound
-
     ofs << "  <bound id=\"lower\"";
 
     ofs << " value=\"";
-    for ( size_t i = 0; i < bounds.size(); i++ )
+    for (const auto & bound : this->m_InputObject->GetParameterBounds() )
       {
-      ofs << " " << bounds[i].first;
+      ofs << " " << bound.first;
       }
     ofs << "\"";
 
@@ -104,9 +100,9 @@ int ParticleSwarmOptimizerSAXWriter::WriteFile()
     ofs << "  <bound id=\"upper\"";
 
     ofs << " value=\"";
-    for ( size_t i = 0; i < bounds.size(); i++ )
+    for (const auto & bound : this->m_InputObject->GetParameterBounds() )
       {
-      ofs << " " << bounds[i].second;
+      ofs << " " << bound.second;
       }
     ofs << "\"";
 

Examples/Statistics/KdTree.cxx

@@ -322,12 +322,12 @@ int main()
             << "query point = [" << queryPoint << "]" << std::endl
             << "search radius = " << radius << std::endl;
   std::cout << "measurement vector : distance" << std::endl;
-  for ( unsigned int i = 0; i < neighbors.size(); ++i )
+  for ( auto neighbor : neighbors)
     {
-    std::cout << "[" << tree->GetMeasurementVector( neighbors[i] )
+    std::cout << "[" << tree->GetMeasurementVector( neighbor )
               << "] : "
               << distanceMetric->Evaluate(
-                  tree->GetMeasurementVector( neighbors[i]))
+                  tree->GetMeasurementVector( neighbor))
               << std::endl;
     }
   // Software Guide : EndCodeSnippet
@@ -347,12 +347,12 @@ int main()
             << "query point = [" << queryPoint << "]" << std::endl
             << "search radius = " << radius << std::endl;
   std::cout << "measurement vector : distance" << std::endl;
-  for ( unsigned int i = 0; i < neighbors.size(); ++i )
+  for ( auto neighbor : neighbors)
     {
-    std::cout << "[" << centroidTree->GetMeasurementVector( neighbors[i] )
+    std::cout << "[" << centroidTree->GetMeasurementVector( neighbor )
               << "] : "
               << distanceMetric->Evaluate(
-                  centroidTree->GetMeasurementVector( neighbors[i]))
+                  centroidTree->GetMeasurementVector( neighbor))
               << std::endl;
     }
   // Software Guide : EndCodeSnippet

Examples/Statistics/ScalarImageMarkovRandomField1.cxx

@@ -377,10 +377,9 @@ int main( int argc, char * argv [] )
     {
     totalWeight += *wcIt;
     }
-  for(std::vector< double >::iterator wIt = weights.begin();
-      wIt != weights.end(); ++wIt )
+  for(double & weight : weights)
     {
-    *wIt = static_cast< double > ( (*wIt) * meanDistance / (2 * totalWeight));
+    weight = static_cast< double > ( weight * meanDistance / (2 * totalWeight));
     }
 
   mrfFilter->SetMRFNeighborhoodWeight( weights );

Modules/Core/Common/include/itkOctreeNode.h

@@ -126,10 +126,10 @@ class ITKCommon_EXPORT OctreeNodeBranch
   OctreeNodeBranch() {}
   OctreeNodeBranch(OctreeBase *parent)
   {
-    for ( int i = 0; i < 8; i++ )
-      {
-      m_Leaves[i].SetParentOctree(parent);
-      }
+    for (auto & leaf : m_Leaves)
+    {
+      leaf.SetParentOctree(parent);
+    }
   }
 
   inline OctreeNode * GetLeaf(enum LeafIdentifier LeafID)

Modules/Core/Common/include/itkTriangleHelper.hxx

@@ -201,21 +201,21 @@ TriangleHelper< TPoint >::ComputeConstrainedCircumCenter(const PointType & iP1,
                                                          const PointType & iP2, const PointType & iP3)
 {
   PointType    oPt;
-  CoordRepType a = iP2.SquaredEuclideanDistanceTo (iP3);
-  CoordRepType b = iP1.SquaredEuclideanDistanceTo (iP3);
-  CoordRepType c = iP2.SquaredEuclideanDistanceTo (iP1);
-
-  CoordRepType Weight[3];
+  const CoordRepType a = iP2.SquaredEuclideanDistanceTo (iP3);
+  const CoordRepType b = iP1.SquaredEuclideanDistanceTo (iP3);
+  const CoordRepType c = iP2.SquaredEuclideanDistanceTo (iP1);
 
-  Weight[0] = a * ( b + c - a );
-  Weight[1] = b * ( c + a - b );
-  Weight[2] = c * ( a + b - c );
+  CoordRepType Weight[3] = {
+    a * ( b + c - a ),
+    b * ( c + a - b ),
+    c * ( a + b - c )
+  };
 
-  for ( unsigned int i = 0; i < 3; i++ )
+  for (auto & i : Weight)
     {
-    if ( Weight[i] < 0.0 )
+    if ( i < 0.0 )
       {
-      Weight[i] = 0.;
+      i = 0.;
       }
     }