backins.cpp

来自「stl自带源码」· C++ 代码 · 共 46 行

/* The following code example is taken from the book
 * "The C++ Standard Library - A Tutorial and Reference"
 * by Nicolai M. Josuttis, Addison-Wesley, 1999
 *
 * (C) Copyright Nicolai M. Josuttis 1999.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include <iostream>
#include <vector>
#include <algorithm>
#include "print.hpp"
using namespace std;

int main()
{
    vector<int> coll;

    // create back inserter for coll
    // - inconvenient way
    back_insert_iterator<vector<int> > iter(coll);

    // insert elements with the usual iterator interface
    *iter = 1;
    iter++;
    *iter = 2;
    iter++;
    *iter = 3;
    PRINT_ELEMENTS(coll);

    // create back inserter and insert elements
    // - convenient way
    back_inserter(coll) = 44;
    back_inserter(coll) = 55;
    PRINT_ELEMENTS(coll);

    // use back inserter to append all elements again
    // - reserve enough memory to avoid reallocation
    coll.reserve(2*coll.size());
    copy (coll.begin(), coll.end(),    // source
          back_inserter(coll));        // destination
    PRINT_ELEMENTS(coll);
}