Iterator in C language

Question

Has anyone tried providing support for Iterator in C. I am not looking for exact C++ STL::Iterator but minimal support for some idea to start would be good point for me .

I am developing container library same like stl but with minimal support, So I need this kind of functionality in those container.

I am looking forward of defining certain sets of algorithms interfaces ( similar to STL ). For example sort , which will take begin and end iterator and should work with any container.

Answer 1

Pointers can serve this function. container.begin() is easy, and container.end() doesn't take too much work.

Consider

Value array[N];
typedef Value* iterator;
iterator array_begin(Value a[]){ return &a[0];}
iterator array_end(Value a[], int n){ return &a[n];}
iterator array_next(iterator i) { return ++i;}

iterator it = array_begin(a);
iterator end = array_end(a,N);
for (;it < end; it=array_next(it))
{
    Value v = *it;
}

For other containers like lists, you can use NULL as end. Same for trees, but the next function needs to maintain state. (or the iterator is a pointer to a struct with state updated by calls to next(it)).