add static_cast for int to size_t

src/field_factory.inl

@@ -41,9 +41,9 @@ inline Field_t FieldFactory::init(const CdoVar& var, const MemType memType) {
 
 inline Field3D_t FieldFactory::init3D(const CdoVar& var) {
   if(var.memType == MemType::Float) {
-    return Field3D<float>{var.gridID, var.gridsize, var.missval, var.gridsize * var.nwpv, var.nlevels};
+    return Field3D<float>{var.gridID, var.gridsize, var.missval, var.gridsize * var.nwpv, static_cast<size_t>(var.nlevels)};
   } else if (var.memType == MemType::Double) {
-    return Field3D<double>{var.gridID, var.gridsize, var.missval, var.gridsize * var.nwpv, var.nlevels};
+    return Field3D<double>{var.gridID, var.gridsize, var.missval, var.gridsize * var.nwpv, static_cast<size_t>(var.nlevels)};
   } else {
     throw std::runtime_error("Not supported type");
   }