diff --git a/cpp/src/graphar/label.cc b/cpp/src/graphar/label.cc
index 64f3c1abe..83f597fcb 100644
--- a/cpp/src/graphar/label.cc
+++ b/cpp/src/graphar/label.cc
@@ -22,6 +22,9 @@
 #include <cassert>
 #include <cstring>
 #include <memory>
+#include <vector>
+
+namespace graphar {
 
 /// Read a parquet file by ParquetReader & get valid indices
 /// The first column_num labels are concerned.
@@ -44,9 +47,9 @@ int read_parquet_file_and_get_valid_indices(
 
   // Initialize the column row counts
   std::vector<int> col_row_counts(num_columns, 0);
-  bool** value = new bool*[num_columns];
+  std::vector<std::unique_ptr<bool[]>> value(num_columns);
   for (int i = 0; i < num_columns; i++) {
-    value[i] = new bool[row_num];
+    value[i] = std::make_unique<bool[]>(row_num);
   }
 
   // Iterate over all the RowGroups in the file
@@ -73,9 +76,9 @@ int read_parquet_file_and_get_valid_indices(
         // Read BATCH_SIZE values at a time. The number of rows read is
         // returned. values_read contains the number of non-null rows
 
-        rows_read = bool_reader->ReadBatch(BATCH_SIZE, nullptr, nullptr,
-                                           value[k] + col_row_counts[col_id],
-                                           &values_read);
+        rows_read = bool_reader->ReadBatch(
+            BATCH_SIZE, nullptr, nullptr,
+            value[k].get() + col_row_counts[col_id], &values_read);
 
         // There are no NULL values in the rows written
         col_row_counts[col_id] += rows_read;
@@ -99,11 +102,7 @@ int read_parquet_file_and_get_valid_indices(
     }
   }
 
-  // destroy the allocated space
-  for (int i = 0; i < num_columns; i++) {
-    delete[] value[i];
-  }
-  delete[] value;
-
   return count;
 }
+
+}  // namespace graphar
diff --git a/cpp/src/graphar/label.h b/cpp/src/graphar/label.h
index ec69e626b..0429d93f3 100644
--- a/cpp/src/graphar/label.h
+++ b/cpp/src/graphar/label.h
@@ -26,8 +26,7 @@
 #include <parquet/api/writer.h>
 #include <parquet/properties.h>
 
-#include <iostream>
-#include <set>
+#include <functional>
 #include <vector>
 
 using parquet::ConvertedType;
@@ -37,6 +36,8 @@ using parquet::Type;
 using parquet::schema::GroupNode;
 using parquet::schema::PrimitiveNode;
 
+namespace graphar {
+
 constexpr int BATCH_SIZE = 1024;  // the batch size
 
 /// The query type
@@ -60,4 +61,6 @@ int read_parquet_file_and_get_valid_indices(
     uint64_t* bitmap = nullptr,
     const QUERY_TYPE query_type = QUERY_TYPE::COUNT);
 
+}  // namespace graphar
+
 #endif  // CPP_SRC_GRAPHAR_LABEL_H_