Preferred foreach Index Type

Question

What is the preferred type for loop indexes when using foreach in D, int, uint or simply automatic by omitting the type?

Answer 1

In general, indices should be size_t. The same with length. You're going to have issues with 32-bit vs 64-bit machines if you try and use int or uint. size_t is what the language uses for array indices and length. It's aliased to uint on 32-bit machines and ulong on 64-bit machines.

So, if you're going to give an index a type, give it size_t. However, the type will be inferred to be size_t by foreach when iterating over an array. So, in most cases, there's no reason to list the type.