fix some clang-tidy cppcoreguidelines-pro-type-member-init warnings

.clang-tidy

@@ -38,4 +38,3 @@ WarningsAsErrors: >-
   *,
   -clang-diagnostic-return-type,
   -cppcoreguidelines-pro-bounds-pointer-arithmetic,
-  -cppcoreguidelines-pro-type-member-init,

include/hdf4cpp/HdfAttribute.h

@@ -51,8 +51,8 @@ class HdfAttribute : public HdfObject {
         int32 size() const;
 
       private:
-        int32 _size;
-        int32 dataType;
+        int32 _size{};
+        int32 dataType{};
 
         void get(void *dest);
         int32 getDataType() const;
@@ -81,8 +81,8 @@ class HdfAttribute : public HdfObject {
         int32 size() const;
 
       private:
-        int32 _size;
-        int32 dataType;
+        int32 _size{};
+        int32 dataType{};
         void get(void *dest);
         int32 getDataType() const;
     };

include/hdf4cpp/HdfItem.h

@@ -216,7 +216,7 @@ class HdfItem : public HdfObject {
 
       private:
         int32 _size;
-        int32 dataType;
+        int32 dataType{};
         std::string name;
         std::vector<int32> dims;
     };
@@ -332,12 +332,11 @@ class HdfItem : public HdfObject {
         }
 
       private:
-        int32 _size;
         std::string name;
 
-        int32 nrRecords;
-        int32 interlace;
-        int32 recordSize;
+        int32 nrRecords{};
+        int32 interlace{};
+        int32 recordSize{};
     };
 
     HdfItem(HdfItemBase *item, int32 sId, int32 vId);