96 lines
2.3 KiB
C++
96 lines
2.3 KiB
C++
// Boost shared_ptr_example.cpp --------------------------------------------//
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// Copyright Beman Dawes 2001. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/libs/smart_ptr for documentation.
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// Revision History
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// 21 May 01 Initial complete version (Beman Dawes)
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// The original code for this example appeared in the shared_ptr documentation.
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// Ray Gallimore pointed out that foo_set was missing a Compare template
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// argument, so would not work as intended. At that point the code was
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// turned into an actual .cpp file so it could be compiled and tested.
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#include <vector>
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#include <set>
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#include <iostream>
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#include <algorithm>
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#include <boost/shared_ptr.hpp>
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// The application will produce a series of
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// objects of type Foo which later must be
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// accessed both by occurrence (std::vector)
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// and by ordering relationship (std::set).
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struct Foo
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{
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Foo( int _x ) : x(_x) {}
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~Foo() { std::cout << "Destructing a Foo with x=" << x << "\n"; }
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int x;
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/* ... */
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};
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typedef boost::shared_ptr<Foo> FooPtr;
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struct FooPtrOps
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{
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bool operator()( const FooPtr & a, const FooPtr & b )
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{ return a->x > b->x; }
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void operator()( const FooPtr & a )
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{ std::cout << a->x << "\n"; }
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};
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int main()
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{
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std::vector<FooPtr> foo_vector;
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std::set<FooPtr,FooPtrOps> foo_set; // NOT multiset!
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FooPtr foo_ptr( new Foo( 2 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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foo_ptr.reset( new Foo( 1 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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foo_ptr.reset( new Foo( 3 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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foo_ptr.reset ( new Foo( 2 ) );
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foo_vector.push_back( foo_ptr );
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foo_set.insert( foo_ptr );
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std::cout << "foo_vector:\n";
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std::for_each( foo_vector.begin(), foo_vector.end(), FooPtrOps() );
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std::cout << "\nfoo_set:\n";
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std::for_each( foo_set.begin(), foo_set.end(), FooPtrOps() );
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std::cout << "\n";
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// Expected output:
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//
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// foo_vector:
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// 2
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// 1
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// 3
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// 2
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//
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// foo_set:
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// 3
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// 2
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// 1
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//
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// Destructing a Foo with x=2
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// Destructing a Foo with x=1
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// Destructing a Foo with x=3
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// Destructing a Foo with x=2
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return 0;
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}
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