distance (STL Samples)

Veranschaulicht, wie die Funktion Abstand Standardvorlagenbibliothek (STL) in Visual C++ verwendet.

template<class Init, class Dist>
   Dist distance(
      InIt first,
      InIt last,
      Dist& n
   );

Hinweise

Hinweis
Die Klasse/Parameternamen im Prototyp stimmen nicht mit der Version in der Headerdatei ab.Einige wurden geändert, um die Lesbarkeit zu verbessern.

Diese Funktion gibt den Abstand zwischen zwei Iteratoren zurück, indem sie bestimmt, wieoft der erste Iterator kann erhöht werden müssen, bis er gleich den letzten Iterator war.

Beispiel

// distance.cpp
// compile with: /EHsc

#pragma warning (disable:4786)
#include <iostream>
#include <vector>
#include <iterator>
#include <string>

using namespace std;

typedef vector<string > VTRLIST;

int main() {
    VTRLIST Vector;
    VTRLIST::iterator iVector;
    VTRLIST::difference_type dTheDiff;

    Vector.push_back("A1");
    Vector.push_back("B2");
    Vector.push_back("C3");
    Vector.push_back("D4");
    Vector.push_back("E5");
    Vector.push_back("F6");
    Vector.push_back("G7");

    // Print out the list
    iVector=Vector.begin();
    cout << "The list is: ";
    for (int i = 0; i < 7 ; i++, iVector++)
        cout << *iVector  << "  ";

    // Initialize the iterator the first element"
    iVector=Vector.begin();
    cout << "\n\nAdvance to the 3rd element." << endl;
    advance( iVector, 2);
    cout << "The element is " << *iVector << endl;
    dTheDiff = distance( Vector.begin(), iVector);
    cout << "The distance from the beginning is " << dTheDiff << endl;

    cout << "Calculate it in reverse order " << endl;
    dTheDiff = distance( iVector, Vector.begin());
    cout << "The distance is " << dTheDiff << endl;

    cout << "\nUse distance() to count from the 3rd element to the end."
         << endl;
    dTheDiff = distance( iVector, Vector.end());

    // Note that end() returns one past the end of the sequence
    cout << "The distance is " << dTheDiff << endl;

    cout <<"\nUse distance() to count the total length." << endl;
    dTheDiff = distance( Vector.begin(), Vector.end() );
    cout << "The total distance is " << dTheDiff << endl;
}

Output

The list is: A1  B2  C3  D4  E5  F6  G7  

Advance to the 3rd element.
The element is C3
The distance from the beginning is 2
Calculate it in reverse order 
The distance is -2

Use distance() to count from the 3rd element to the end.
The distance is 5

Use distance() to count the total length.
The total distance is 7

Anforderungen

Header: <iterator>

Siehe auch

Konzepte

Standardvorlagenbibliotheks-Beispiele