Why use iterators instead of array indices?

Question

Take the following two lines of code:

for (int i = 0; i < some_vector.size(); i++)
{
    //do stuff
}

And this:

for (som         


        

Answer 1

Because it is more object-oriented. if you are iterating with an index you are assuming:

a) that those objects are ordered
b) that those objects can be obtained by an index
c) that the index increment will hit every item
d) that that index starts at zero

With an iterator, you are saying "give me everything so I can work with it" without knowing what the underlying implementation is. (In Java, there are collections that cannot be accessed through an index)

Also, with an iterator, no need to worry about going out of bounds of the array.