Why do we need iterators in c#?

Question

Can somebody provide a real life example regarding use of iterators. I tried searching google but was not satisfied with the answers.

Answer 1

A couple of things they're great for:
a) For 'perceived performance' while maintaining code tidiness - the iteration of something separated from other processing logic.
b) When the number of items you're going to iterate through is not known.

Although both can be done through other means, with iterators the code can be made nicer and tidier as someone calling the iterator don't need to worry about how it finds the stuff to iterate through...

Real life example: enumerating directories and files, and finding the first [n] that fulfill some criteria, e.g. a file containing a certain string or sequence etc...