Increment n by the number of steps it takes to traverse from first to last .

Declaration


  
#include <algorithm>

template< class InputIterator, class Distance >
void distance
  (
  InputIterator first,
  InputIterator last,
  Distance& n
  );

Complexity

Time complexity is constant for random access iterators and linear for all other iterators. Space complexity is constant.

Example <ospace/osstd/examples/distance.cpp>


    #include <iostream>
#include <iterator>
#include <vector>

void
main()
  {
  vector< int > v( 10 );
  for ( int i = 0; i < v.size(); ++i )
    v[ i ] = 100 + i;
  // Find something in the middle.
  vector< int >::iterator location = v.begin();
  advance( location, 8 );
  vector< int >::difference_type n = 0;

  distance( v.begin(), location, n );
  cout << n << "\n";

  // Notice that n is incremented, not reset.
  distance( location, v.end(), n );
  cout << n << "\n";

  distance( v.begin(), v.end(), n );
  cout << n << "\n";
  }

8
10
20

distance

Library

Declaration

Complexity

Example <ospace/osstd/examples/distance.cpp>