The C++ Standard Library consists of the header, <iterator>. An iterator is an object that points to an element in a range of elements. The most obvious form of an iterator is a pointer. The distance() method is present under this header and it calculates the number of elements between two iterators.
Syntax:
distance( iterator_begin, iterator_end );
Parameters: The distance() method accepts 2 parameters
- iterator_begin: Iterator to the initial element
- iterator_end: Iterator to the final element (Note: It must be reachable from iterator_begin)
Return value: Number of elements between the two iterators
Example of distance() method
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
int main()
{
vector<int> v;
v.push_back(3);
v.push_back(2);
v.push_back(1);
v.push_back(4);
v.push_back(5);
vector<int>::iterator it1= v.begin();
vector<int>::iterator it2= v.begin()+3;
cout<<"No. of elements between it1 and it2: "<< distance(it1, it2);
}
Output:
No. of elements between it1 and it2: 3
