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Bidirectional Iterators in C++
Here we will see the concept of Bidirectional iterators in C++.
- The bidirectional iterators support all of the features of forward iterators, and also prefix and postfix decrement operators.
- This type of iterator can access elements in both directions, like towards the end and towards the beginning.
- The random access iterator is also a type of bidirectional iterator.
- Bidirectional iterators have features of forward iterator, but only difference is this iterator can also be decremented.
The Bidirectional iterators has some properties. These are like below.
| Property | Expression |
|---|---|
| The bidirectional iterator is default-constructible, copy-assignable, and also destructible | A p A q(p) q = p |
| We can compare them using equality and inequality operators | p == q p != q |
| This can be dereferenced. We can use the dereference operator (*) to get value. | *p |
| The mutable iterator can be dereferenced as lvalue | *p = t |
| We can increment or decrement using increment operator (++), and decrement operator (--) | p++ q-- |
Example Code
#include <iostream>
#include<iterator>
#include<vector>
using namespace std;
int main() {
vector<int> vec{10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
vector<int> ::iterator it;
vector<int> :: reverse_iterator rev_it;
for(it = vec.begin(); it != vec.end(); it++)
cout<<*it<<" ";
cout<< endl;
for(rev_it = vec.rbegin(); rev_it!= vec.rend(); rev_it++)
cout<<*rev_it<<" ";
}
Output
10 20 30 40 50 60 70 80 90 100 100 90 80 70 60 50 40 30 20 10
Updated on: 2019-07-30T22:30:26+05:30
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