Читать книгу Excel 2019 Power Programming with VBA - Michael Alexander, Dick Kusleika - Страница 144

The Decimal data type is unusual because you can't declare it. In fact, it is a subtype of a variant. You need to use the VBA CDec function to convert a variant to the Decimal data type.

Generally, it's best to use the data type that uses the smallest number of bytes yet still can handle all the data that will be assigned to it. When VBA works with data, execution speed is partially a function of the number of bytes that VBA has at its disposal. In other words, the fewer the bytes used by the data, the faster that VBA can access and manipulate the data.

For worksheet calculation, Excel uses the Double data type, so that's a good choice for processing numbers in VBA when you don't want to lose any precision. For integer calculations, you can use the Integer type (which is limited to values less than or equal to 32,767). Otherwise, use the Long data type. In fact, using the Long data type even for values less than 32,767 is recommended because this data type may be a bit faster than using the Integer type. When dealing with Excel worksheet row numbers, you want to use the Long data type because the number of rows in a worksheet exceeds the maximum value for the Integer data type.