STYLE: Replace postfix by prefix increment in for loops in Core/Common

Followed common C++ guidelines, including:

Google C++ Style Guide: "Use the prefix form (++i) of the increment and
decrement operators unless you need postfix semantics."
https://google.github.io/styleguide/cppguide.html#Preincrement_and_Predecrement

Herb Sutter, Andrei Alexandrescu - C++ Coding Standards: 101 Rules,
Guidelines, and Best Practices: "Prefer the canonical form of ++ and --.
Prefer calling the prefix forms"
https://www.oreilly.com/library/view/c-coding-standards/0321113586/ch29.html

Applied at GNU bash, by the following command:

	find . \( -iname *.cxx -or -iname *.hxx -or -iname *.h \) -exec perl -pi -w -e 's/(\s+for \(.*; .+); (\w+)\+\+\)/$1; ++$2)/g;' {} \;

Manually replaced a few more postfix increments, which were not detected
by this regex command, as remarked by Mikhail Isakov (issakomi).

Modules/Core/Common/include/itkArray.h

@@ -104,7 +104,7 @@ class ITK_TEMPLATE_EXPORT Array : public vnl_vector<TValue>
   {
     this->m_LetArrayManageMemory = true;
     this->SetSize(r.GetSize());
-    for (SizeValueType i = 0; i < r.GetSize(); i++)
+    for (SizeValueType i = 0; i < r.GetSize(); ++i)
     {
       this->operator[](i) = static_cast<TValue>(r[i]);
     }

Modules/Core/Common/include/itkBSplineInterpolationWeightFunction.hxx

@@ -44,7 +44,7 @@ BSplineInterpolationWeightFunction<TCoordRep, VSpaceDimension, VSplineOrder>::BS
 
   for (const IndexType index : ZeroBasedIndexRange<VSpaceDimension>(m_SupportSize))
   {
-    for (unsigned int j = 0; j < SpaceDimension; j++)
+    for (unsigned int j = 0; j < SpaceDimension; ++j)
     {
       m_OffsetToIndexTable[counter][j] = index[j];
     }
@@ -95,7 +95,7 @@ BSplineInterpolationWeightFunction<TCoordRep, VSpaceDimension, VSplineOrder>::Ev
   unsigned int j, k;
 
   // Find the starting index of the support region
-  for (j = 0; j < SpaceDimension; j++)
+  for (j = 0; j < SpaceDimension; ++j)
   {
     // Note that the expression passed to Math::Floor is adapted to work around
     // a compiler bug which caused endless compilations (apparently), by
@@ -105,22 +105,22 @@ BSplineInterpolationWeightFunction<TCoordRep, VSpaceDimension, VSplineOrder>::Ev
 
   // Compute the weights
   Matrix<double, SpaceDimension, SplineOrder + 1> weights1D;
-  for (j = 0; j < SpaceDimension; j++)
+  for (j = 0; j < SpaceDimension; ++j)
   {
     double x = index[j] - static_cast<double>(startIndex[j]);
 
-    for (k = 0; k <= SplineOrder; k++)
+    for (k = 0; k <= SplineOrder; ++k)
     {
       weights1D[j][k] = m_Kernel->Evaluate(x);
       x -= 1.0;
     }
   }
 
-  for (k = 0; k < m_NumberOfWeights; k++)
+  for (k = 0; k < m_NumberOfWeights; ++k)
   {
     weights[k] = 1.0;
 
-    for (j = 0; j < SpaceDimension; j++)
+    for (j = 0; j < SpaceDimension; ++j)
     {
       weights[k] *= weights1D[j][m_OffsetToIndexTable[k][j]];
     }

Modules/Core/Common/include/itkBoundingBox.hxx

@@ -42,7 +42,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Pri
   Superclass::PrintSelf(os, indent);
 
   os << indent << "Bounding Box: ( ";
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     os << m_Bounds[2 * i] << "," << m_Bounds[2 * i + 1] << " ";
   }
@@ -85,15 +85,15 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Com
   PointType center = this->GetCenter();
   PointType radius;
 
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     radius[i] = m_Bounds[2 * i + 1] - center[i];
   }
 
-  for (SizeValueType j = 0; j < NumberOfCorners; j++)
+  for (SizeValueType j = 0; j < NumberOfCorners; ++j)
   {
     PointType pnt;
-    for (unsigned int i = 0; i < PointDimension; i++)
+    for (unsigned int i = 0; i < PointDimension; ++i)
     {
       pnt[i] = center[i] + std::pow(-1.0, ((double)(j / (int(std::pow(2.0, (double)i)))))) * radius[i];
     }
@@ -158,7 +158,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Com
 
     PointsContainerConstIterator      ci = m_PointsContainer->Begin();
     Point<TCoordRep, VPointDimension> point = ci->Value(); // point value
-    for (unsigned int i = 0; i < PointDimension; i++)
+    for (unsigned int i = 0; i < PointDimension; ++i)
     {
       m_Bounds[2 * i] = point[i];
       m_Bounds[2 * i + 1] = point[i];
@@ -170,7 +170,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Com
     while (ci != m_PointsContainer->End())
     {
       point = ci->Value(); // point value
-      for (unsigned int i = 0; i < PointDimension; i++)
+      for (unsigned int i = 0; i < PointDimension; ++i)
       {
         if (point[i] < m_Bounds[2 * i])
         {
@@ -197,7 +197,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Get
   this->ComputeBoundingBox();
 
   PointType center;
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     center[i] = (m_Bounds[2 * i] + m_Bounds[2 * i + 1]) / 2.0;
   }
@@ -212,7 +212,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Get
   this->ComputeBoundingBox();
 
   PointType minimum;
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     minimum[i] = m_Bounds[2 * i];
   }
@@ -224,7 +224,7 @@ template <typename TPointIdentifier, unsigned int VPointDimension, typename TCoo
 void
 BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::SetMinimum(const PointType & point)
 {
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     m_Bounds[2 * i] = point[i];
   }
@@ -239,7 +239,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Get
   this->ComputeBoundingBox();
 
   PointType maximum;
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     maximum[i] = m_Bounds[2 * i + 1];
   }
@@ -251,7 +251,7 @@ template <typename TPointIdentifier, unsigned int VPointDimension, typename TCoo
 void
 BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::SetMaximum(const PointType & point)
 {
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     m_Bounds[2 * i + 1] = point[i];
   }
@@ -265,7 +265,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Con
 {
   bool changed = false;
 
-  for (unsigned int i = 0; i < PointDimension; i++)
+  for (unsigned int i = 0; i < PointDimension; ++i)
   {
     if (point[i] < m_Bounds[2 * i])
     {
@@ -293,7 +293,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Get
 
   if (this->ComputeBoundingBox())
   {
-    for (unsigned int i = 0; i < PointDimension; i++)
+    for (unsigned int i = 0; i < PointDimension; ++i)
     {
       dist2 += (m_Bounds[2 * i] - m_Bounds[2 * i + 1]) * (m_Bounds[2 * i] - m_Bounds[2 * i + 1]);
     }
@@ -367,7 +367,7 @@ BoundingBox<TPointIdentifier, VPointDimension, TCoordRep, TPointsContainer>::Dee
 #endif
 
   // Copy the bounds into the clone
-  for (unsigned int i = 0; i < 2 * PointDimension; i++)
+  for (unsigned int i = 0; i < 2 * PointDimension; ++i)
   {
     clone->m_Bounds[i] = this->m_Bounds[i];
   }

Modules/Core/Common/include/itkBresenhamLine.hxx

@@ -60,14 +60,14 @@ BresenhamLine<VDimension>::BuildLine(LType Direction, unsigned int length)
   // we are going to start at 0
   m_CurrentImageIndex.Fill(0);
   StartIndex.Fill(0);
-  for (unsigned i = 0; i < VDimension; i++)
+  for (unsigned i = 0; i < VDimension; ++i)
   {
     LastIndex[i] = (IndexValueType)(length * Direction[i]);
   }
   // Find the dominant direction
   IndexValueType maxDistance = 0;
   unsigned int   maxDistanceDimension = 0;
-  for (unsigned i = 0; i < VDimension; i++)
+  for (unsigned i = 0; i < VDimension; ++i)
   {
     auto distance = static_cast<long>(itk::Math::abs(LastIndex[i]));
     if (distance > maxDistance)
@@ -118,7 +118,7 @@ BresenhamLine<VDimension>::BuildLine(IndexType p0, IndexType p1)
 {
   itk::Point<float, VDimension> point0;
   itk::Point<float, VDimension> point1;
-  for (unsigned int i = 0; i < VDimension; i++)
+  for (unsigned int i = 0; i < VDimension; ++i)
   {
     point0[i] = p0[i];
     point1[i] = p1[i];
@@ -128,7 +128,7 @@ BresenhamLine<VDimension>::BuildLine(IndexType p0, IndexType p1)
   OffsetArray offsets = this->BuildLine(point1 - point0, distance);
 
   IndexArray indices(offsets.size());
-  for (unsigned int i = 0; i < offsets.size(); i++)
+  for (unsigned int i = 0; i < offsets.size(); ++i)
   {
     indices[i] = p0 + offsets[i];
   }

Modules/Core/Common/include/itkByteSwapper.hxx

@@ -287,7 +287,7 @@ void
 ByteSwapper<T>::Swap2Range(void * ptr, BufferSizeType num)
 {
   auto * pos = static_cast<char *>(ptr);
-  for (BufferSizeType i = 0; i < num; i++)
+  for (BufferSizeType i = 0; i < num; ++i)
   {
     const char one_byte = pos[0];
     pos[0] = pos[1];
@@ -312,7 +312,7 @@ ByteSwapper<T>::SwapWrite2Range(void * ptr, BufferSizeType num, OStreamType * fp
     memcpy(cpy, ptr, chunkSize * 2);
 
     char * pos = cpy;
-    for (BufferSizeType i = 0; i < chunkSize; i++)
+    for (BufferSizeType i = 0; i < chunkSize; ++i)
     {
       const char one_byte = pos[0];
       pos[0] = pos[1];
@@ -356,7 +356,7 @@ ByteSwapper<T>::Swap4Range(void * ptr, BufferSizeType num)
 {
   auto * pos = static_cast<char *>(ptr);
 
-  for (BufferSizeType i = 0; i < num; i++)
+  for (BufferSizeType i = 0; i < num; ++i)
   {
     char one_byte = pos[0];
     pos[0] = pos[3];
@@ -387,7 +387,7 @@ ByteSwapper<T>::SwapWrite4Range(void * ptr, BufferSizeType num, OStreamType * fp
     memcpy(cpy, ptr, chunkSize * 4);
 
     char * pos = cpy;
-    for (BufferSizeType i = 0; i < chunkSize; i++)
+    for (BufferSizeType i = 0; i < chunkSize; ++i)
     {
       char one_byte = pos[0];
       pos[0] = pos[3];
@@ -443,7 +443,7 @@ ByteSwapper<T>::Swap8Range(void * ptr, BufferSizeType num)
 {
   auto * pos = static_cast<char *>(ptr);
 
-  for (BufferSizeType i = 0; i < num; i++)
+  for (BufferSizeType i = 0; i < num; ++i)
   {
     char one_byte = pos[0];
     pos[0] = pos[7];

Modules/Core/Common/include/itkCellInterface.hxx

@@ -66,7 +66,7 @@ template <typename TPixelType, typename TCellTraits>
 void
 CellInterface<TPixelType, TCellTraits>::SetPointIdsContainer(const PointIdentifierContainerType & container)
 {
-  for (unsigned int i = 0; i < container.Size(); i++)
+  for (unsigned int i = 0; i < container.Size(); ++i)
   {
     this->SetPointId(i, container[i]);
   }

Modules/Core/Common/include/itkColorTable.hxx

@@ -137,7 +137,7 @@ ColorTable<TPixel>::UseGrayColors(unsigned int n)
   // Converting from TPixel to RealType may introduce a rounding error, so do static_cast
   constexpr auto max_value_converted =
     static_cast<typename NumericTraits<TPixel>::RealType>(NumericTraits<TPixel>::max());
-  for (i = 0; i < m_NumberOfColors; i++)
+  for (i = 0; i < m_NumberOfColors; ++i)
   {
     typename NumericTraits<TPixel>::RealType realGray(minimum + i * delta);
 
@@ -182,7 +182,7 @@ ColorTable<TPixel>::UseHeatColors(unsigned int n)
   // Converting from TPixel to RealType may introduce a rounding error, so do static_cast
   constexpr auto max_value_converted =
     static_cast<typename NumericTraits<TPixel>::RealType>(NumericTraits<TPixel>::max());
-  for (i = 0; i < n / 2.0; i++)
+  for (i = 0; i < n / 2.0; ++i)
   {
     //
     // avoid overflow
@@ -200,7 +200,7 @@ ColorTable<TPixel>::UseHeatColors(unsigned int n)
     m_ColorName[i] = name.str();
   }
 
-  for (i = 0; i < n / 2; i++)
+  for (i = 0; i < n / 2; ++i)
   {
     typename NumericTraits<TPixel>::RealType rdouble(1.0 * scale + shift);
     TPixel                                   r(NumericTraits<TPixel>::max());
@@ -240,7 +240,7 @@ ColorTable<TPixel>::UseRandomColors(unsigned int n)
     minimum = NumericTraits<TPixel>::ZeroValue();
     maximum = NumericTraits<TPixel>::OneValue();
   }
-  for (i = 0; i < n; i++)
+  for (i = 0; i < n; ++i)
   {
     r = static_cast<TPixel>(vnl_sample_uniform(minimum, maximum));
     m_Color[i][0] = r;
@@ -346,7 +346,7 @@ ColorTable<TPixel>::GetClosestColorTableId(TPixel r, TPixel g, TPixel b)
   double       bestMatch = 0.0;
   unsigned int bestMatchColor = 0;
 
-  for (unsigned int i = 0; i < m_NumberOfColors; i++)
+  for (unsigned int i = 0; i < m_NumberOfColors; ++i)
   {
     double match;
     match = (r - (double)m_Color[i].GetRed()) * (r - (double)m_Color[i].GetRed());
@@ -368,7 +368,7 @@ ColorTable<TPixel>::PrintSelf(std::ostream & os, Indent indent) const
   Superclass::PrintSelf(os, indent);
 
   os << indent << "NumberOfColors = " << m_NumberOfColors << std::endl;
-  for (unsigned int i = 0; i < m_NumberOfColors; i++)
+  for (unsigned int i = 0; i < m_NumberOfColors; ++i)
   {
     os << indent << "ColorName[" << i << "] = " << m_ColorName[i] << ", "
        << "Color[" << i << "] = " << m_Color[i] << std::endl;

Modules/Core/Common/include/itkConicShellInteriorExteriorSpatialFunction.hxx

@@ -95,14 +95,14 @@ ConicShellInteriorExteriorSpatialFunction<VDimension, TInput>::PrintSelf(std::os
 
   unsigned int i;
   os << indent << "Origin: [";
-  for (i = 0; i < VDimension - 1; i++)
+  for (i = 0; i < VDimension - 1; ++i)
   {
     os << m_Origin[i] << ", ";
   }
   os << "]" << std::endl;
 
   os << indent << "Gradient at origin: [";
-  for (i = 0; i < VDimension - 1; i++)
+  for (i = 0; i < VDimension - 1; ++i)
   {
     os << m_OriginGradient[i] << ", ";
   }

Modules/Core/Common/include/itkConnectedComponentAlgorithm.h

@@ -48,7 +48,7 @@ setConnectivity(TIterator * it, bool fullyConnected = false)
     // activate all neighbors that are face+edge+vertex
     // connected to the current pixel. do not include the center pixel
     unsigned int centerIndex = it->GetCenterNeighborhoodIndex();
-    for (unsigned int d = 0; d < centerIndex * 2 + 1; d++)
+    for (unsigned int d = 0; d < centerIndex * 2 + 1; ++d)
     {
       offset = it->GetOffset(d);
       it->ActivateOffset(offset);
@@ -83,7 +83,7 @@ setConnectivityPrevious(TIterator * it, bool fullyConnected = false)
     // activate all neighbors that are face+edge+vertex
     // connected to the current pixel. do not include the center pixel
     unsigned int centerIndex = it->GetCenterNeighborhoodIndex();
-    for (unsigned int d = 0; d < centerIndex; d++)
+    for (unsigned int d = 0; d < centerIndex; ++d)
     {
       offset = it->GetOffset(d);
       it->ActivateOffset(offset);
@@ -118,7 +118,7 @@ setConnectivityLater(TIterator * it, bool fullyConnected = false)
     // activate all neighbors that are face+edge+vertex
     // connected to the current pixel. do not include the center pixel
     unsigned int centerIndex = it->GetCenterNeighborhoodIndex();
-    for (unsigned int d = centerIndex + 1; d < 2 * centerIndex + 1; d++)
+    for (unsigned int d = centerIndex + 1; d < 2 * centerIndex + 1; ++d)
     {
       offset = it->GetOffset(d);
       it->ActivateOffset(offset);

Modules/Core/Common/include/itkConstNeighborhoodIterator.h

@@ -111,7 +111,7 @@ class ITK_TEMPLATE_EXPORT ConstNeighborhoodIterator
   ConstNeighborhoodIterator(const SizeType & radius, const ImageType * ptr, const RegionType & region)
   {
     this->Initialize(radius, ptr, region);
-    for (DimensionValueType i = 0; i < Dimension; i++)
+    for (DimensionValueType i = 0; i < Dimension; ++i)
     {
       m_InBounds[i] = false;
     }