Why do we use special types like size_type

Question

Hi I am re-learning c++ through the c++ primer book. The author consistently uses declarations like list ::const_iterator result = find(lst.begin() lst.end() search_value); size_type size=c.count(); Why is he doing that? Why can't we just declare int or float

Alan · Answer

There's a tendency in C++ to give everything a special type name which is generally a typedef for some predefined type (such as int float double etc). This is done extensively in Windows programming where you have numerous typedefs all meaning essentially the same thing. The only good reason for doing this IMO is if the underlying type changes depending on what platform your application is running on which may be the case with a size_type. However it's something I've never much cared for (the language is hard enough without having to remember numerous typedefs!) and it's one reason why I prefer to do most of my programming nowadays in C#.