Add an option to just convert a txt with same output name

main.cpp

@@ -104,7 +104,7 @@ void txt2pcd( std::filesystem::path input, std::filesystem::path output )
 
 void printHelp()
 {
-    std::cout << "Usage: txt2pcd inputCloud.txt outputCloud.pcd\n";
+    std::cout << "Usage: txt2pcd inputCloud.txt [outputCloud.pcd]\n";
 }
 
 int main( int argc, char** argv )
@@ -120,6 +120,14 @@ int main( int argc, char** argv )
             std::cerr << e.what() << "\n";
         }
     }
+    else if ( argc == 2 )
+    {
+        auto basefilename = std::filesystem::path{ argv[ 1 ] };
+        auto outfilename  = basefilename;
+        outfilename.replace_extension( std::filesystem::path{ "pcd" } );
+
+        txt2pcd( basefilename, outfilename );
+    }
     else
     {
         printHelp();