syntax problem

[venkatacplpl]

Hi,
I am a beginner in c++ and i came across some line like this..

vector<int>::iterator itr=v.begin();
\\where v is already initiated instance of vector..

i can understand that they made alias of iterator which is data member of vector
class as itr.



But i havent read in c++ so far that alias of a data member can be made.
(ex: class_name::data_member another_name)

i want to know which concept supoorts this?????
please help...

[mutexe]

it's not making an alias of anything?

[venkatacplpl]

can you plz explain me whats happening there???

vector<int>::iterator =v.begin();

cant i write something like this??
vector<int>::iterator =v.begin();

[venkatacplpl]

the above one makes sense if i assume.....that iterator is a static member in vector class.

[mutexe]

you've written the same thing twice? I'm not understanding what you are actually asking.

[mutexe]

vectors can give you an iterator to make traversal 'easier'.
read this:
http://www.cprogramming.com/tutorial/stl/iterators.html

[venkatacplpl]

vector<int>::iterator itr =v.begin();
is the actual line.......
cant i rewrite it as
vector<int>::iterator =v.begin();?????


second one makes sense to me as iterator is static member in vector class...



thanks

[booradley60]

vector<int>::iterator is a class that is defined within the other class vector<int>. These two classes cooperate with each other to give you some refined behavior for moving over a vector.

So when you say:
vector<int>::iterator itr=v.begin();
what you mean is create an object called itr, that is of type vector<int>::iterator. Then, the vector you want to iterate over, in this case v, exposes a way to initialize your new iterator: = v.begin();

http://www.oodesign.com/iterator-pattern.html

[venkatacplpl]

@booradley60 (52)

now i understood......thanks for explaining with such a detail

thanks again..

[mutexe]

cant i rewrite it as
vector<int>::iterator =v.begin();?????

That is like the difference between:

double myDouble = 3.14;

and

double = 3.14;

clearly the second one is completely wrong.