distance

두 반복기에 의해 주소가 지정 된 위치 사이의 간격들의 수를 결정합니다.

template<class InputIterator> 
   typename iterator_traits<InputIterator>::difference_type 
      distance( 
         InputIterator _First,  
         InputIterator _Last 
      );

매개 변수

• _First
  The first iterator whose distance from the second is to be determined.

• _Last
  The second iterator whose distance from the first is to be determined.

반환 값

The number of times that _First must be incremented until it equal _Last.

설명

The distance function has constant complexity when InputIterator satisfies the requirements for a random-access iterator; otherwise, it has linear complexity and so is potentially expensive.

예제

// iterator_distance.cpp
// compile with: /EHsc
#include <iterator>
#include <list>
#include <iostream>

int main( )
{
   using namespace std;
   int i;

   list<int> L;
   for ( i = -1 ; i < 9 ; ++i ) 
   {
      L.push_back ( 2 * i );
   }
   list <int>::iterator L_Iter, LPOS = L.begin ( );

   cout << "The list L is: ( ";
   for ( L_Iter = L.begin( ) ; L_Iter != L.end( ); L_Iter++ )
      cout << *L_Iter << " ";
   cout << ")." << endl;
   
   cout << "The iterator LPOS initially points to the first element: "
        << *LPOS << "." << endl;

   advance ( LPOS , 7 );
   cout << "LPOS is advanced 7 steps forward to point "
        << " to the eighth element: "
        << *LPOS << "." << endl;

   list<int>::difference_type Ldiff ;
   Ldiff = distance ( L.begin ( ) , LPOS );
   cout << "The distance from L.begin( ) to LPOS is: "
        << Ldiff << "." << endl;
}

요구 사항

헤더: <iterator>

네임스페이스: std

참고 항목

참조

distance(STL 샘플)

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