83 lines
2.7 KiB
C++
83 lines
2.7 KiB
C++
/**************************************************************************
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*
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* distance.cpp - Example program for distance between two iterators.
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*
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* $Id: distance.cpp 550991 2007-06-26 23:58:07Z sebor $
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*
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***************************************************************************
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed
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* with this work for additional information regarding copyright
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* ownership. The ASF licenses this file to you under the Apache
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* License, Version 2.0 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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* implied. See the License for the specific language governing
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* permissions and limitations under the License.
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*
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* Copyright 1994-2006 Rogue Wave Software.
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*
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**************************************************************************/
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#include <cassert>
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#include <iterator>
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#include <iostream>
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#include <vector>
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#include <examples.h>
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int main ()
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{
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// Typedefs for convenience.
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typedef std::vector<int, std::allocator<int> > Vector;
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typedef std::ostream_iterator<Vector::value_type,
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char,
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std::char_traits<char> > os_iter;
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// Initialize a vector using an array.
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const Vector::value_type arr [] = { 3, 4, 5, 6, 7, 8 };
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const Vector v (arr + 0, arr + sizeof arr/ sizeof *arr);
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// Declare a vector iterator, s.b. a ForwardIterator.
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Vector::const_iterator it = v.begin () + 3;
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// Output the original vector.
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std::cout << "For the vector: ";
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std::copy (v.begin (), v.end (), os_iter (std::cout, " "));
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std::cout << '\n';
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std::cout << "\nWhen the iterator is initialized to point to "
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<< *it << '\n';
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// Compute the distance of it from the first element.
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Vector::difference_type dist = 0;
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#ifndef _RWSTD_NO_EXT_VOID_DISTANCE
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// using the extended overload of function template distance()
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// provided by this implmentation, compute the distance between
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// the two iterators
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std::distance (v.begin (), it, dist);
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assert (3 == dist);
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#endif // _RWSTD_NO_EXT_VOID_DISTANCE
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// do the same using the standard function template distance()
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dist = std::distance (v.begin (), it);
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std::cout << "The distance between the beginning and "
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<< *it << " is " << dist << '\n';
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return 0;
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}
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