suggesting zero padding files when writing (#5597)

* suggesting zero padding files when writing

* updating documentation with correct filenames

Author: joerowelll

doc/tutorials/content/cluster_extraction.rst

@@ -171,10 +171,10 @@ You will see something similar to::
   PointCloud representing the Cluster: 290 data points.
   PointCloud representing the Cluster: 120 data points.
 
-You can also look at your outputs cloud_cluster_0.pcd, cloud_cluster_1.pcd,
-cloud_cluster_2.pcd, cloud_cluster_3.pcd and cloud_cluster_4.pcd::
+You can also look at your outputs cloud_cluster_0000.pcd, cloud_cluster_0001.pcd,
+cloud_cluster_0002.pcd, cloud_cluster_0003.pcd and cloud_cluster_0004.pcd::
 
-	$ ./pcl_viewer cloud_cluster_0.pcd cloud_cluster_1.pcd cloud_cluster_2.pcd cloud_cluster_3.pcd cloud_cluster_4.pcd
+	$ ./pcl_viewer cloud_cluster_0000.pcd cloud_cluster_0001.pcd cloud_cluster_0002.pcd cloud_cluster_0003.pcd cloud_cluster_0004.pcd
 
 You are now able to see the different clusters in one viewer. You should see
 something similar to this:

doc/tutorials/content/sources/cluster_extraction/cluster_extraction.cpp

@@ -94,8 +94,8 @@ main ()
 
     std::cout << "PointCloud representing the Cluster: " << cloud_cluster->size () << " data points." << std::endl;
     std::stringstream ss;
-    ss << "cloud_cluster_" << j << ".pcd";
-    writer.write<pcl::PointXYZ> (ss.str (), *cloud_cluster, false); //*
+    ss << std::setw(4) << std::setfill('0') << j;
+    writer.write<pcl::PointXYZ> ("cloud_cluster_" + ss.str () + ".pcd", *cloud_cluster, false); //*
     j++;
   }