pre-allocating the container capacity before the loop

Author: DIlkhush00

common/src/io.cpp

@@ -102,6 +102,8 @@ pcl::concatenateFields (const pcl::PCLPointCloud2 &cloud1,
   //by offset so that we can compute sizes correctly. There is no
   //guarantee that the fields are in the correct order when they come in
   std::vector<const pcl::PCLPointField*> cloud1_fields_sorted;
+  cloud1_fields_sorted.reserve(cloud1.fields.size());
+  
   for (const auto &field : cloud1.fields)
     cloud1_fields_sorted.push_back (&field);
 

visualization/include/pcl/visualization/area_picking_event.h

@@ -81,6 +81,8 @@ namespace pcl
         getCloudNames () const
         {
           std::vector<std::string> names;
+          names.reserve(cloud_indices_.size());
+          
           for (const auto& i : cloud_indices_)
             names.push_back (i.first);
           return names;