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