The following sample code illustrates how to use the
set::swap, set::begin and set::end STL functions in Visual C++.
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Required header
<set>
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Prototype
template<class _K, class _Pr, class _A>
class set {
public:
// Function 1:
void swap(_Myt& _X);
// Function 2:
friend void swap(_Myt& _X, _Myt& _Y);
// Function 3:
const_iterator begin() const;
// Function 4:
const_iterator end() const;
}Note The class/parameter names in the prototype may not match the
version in the header file. Some have been modified to improve readability.
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Description
The swap function swaps the two controlled sequences. The begin
function returns a bidirectional iterator that points at the first element of
the sequence. The end function returns a bidirectional iterator that points
just beyond the end of the sequence.
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Sample code
//////////////////////////////////////////////////////////////////////
//
// Compile options needed: -GX
//
// SetSwapBeginEnd.cpp:
// Illustrates how to use the swap function to exchange the two
// controlled sequences. It also illustrates how to use the
// begin function to get a bidirectional iterator that points at
// the first element of the controlled sequence. Finally, it
// illustrates how to use the end function to get a bidirectional
// iterator that points just beyond the end of the controlled
// sequence.
//
// Functions:
//
// swap Exchanges the two controlled sequences.
// begin Returns a bidirectional iterator that points at the
// first element of the controlled sequence.
// end Returns a bidirectional iterator that points just
// beyond the end of the controlled sequence.
//
// Written by Derek Jamison
// of Microsoft Technical Support,
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
//////////////////////////////////////////////////////////////////////
#pragma warning(disable:4786)
#include <set>
#include <iostream>
#if _MSC_VER > 1020 // if VC++ version is > 4.2
using namespace std; // std c++ libs implemented in std
#endif
typedef set<int,less<int>,allocator<int> > SET_INT;
void main() {
SET_INT s1;
SET_INT s2;
SET_INT::iterator i;
cout << "s1.insert(5)" << endl;
s1.insert(5);
cout << "s1.insert(10)" << endl;
s1.insert(10);
cout << "s1.insert(15)" << endl;
s1.insert(15);
cout << "s2.insert(2)" << endl;
s2.insert(2);
cout << "s2.insert(4)" << endl;
s2.insert(4);
cout << "swap(s1,s2)" << endl;
swap(s1,s2);
// Displays: 2,4
for (i=s1.begin();i!=s1.end();i++)
cout << "s1 has " << *i << " in its set." << endl;
// Displays: 5,10,15
for (i=s2.begin();i!=s2.end();i++)
cout << "s2 has " << *i << " in its set." << endl;
cout << "s1.swap(s2)" << endl;
s1.swap(s2);
// Displays: 5,10,15
for (i=s1.begin();i!=s1.end();i++)
cout << "s1 has " << *i << " in its set." << endl;
// Displays: 2,4
for (i=s2.begin();i!=s2.end();i++)
cout << "s2 has " << *i << " in its set." << endl;
}
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Program output
s1.insert(5)
s1.insert(10)
s1.insert(15)
s2.insert(2)
s2.insert(4)
swap(s1,s2)
s1 has 2 in its set.
s1 has 4 in its set.
s2 has 5 in its set.
s2 has 10 in its set.
s2 has 15 in its set.
s1.swap(s2)
s1 has 5 in its set.
s1 has 10 in its set.
s1 has 15 in its set.
s2 has 2 in its set.
s2 has 4 in its set.
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For the same topic about set::swap, begin, and end, visit
the following MSDN Web site:
http://msdn.microsoft.com/library/en-us/vclang98/html/sample_setCCswap__begin__end_(STL_Sample).asp?frame=true (http://msdn.microsoft.com/library/en-us/vclang98/html/sample_setCCswap__begin__end_(STL_Sample).asp?frame=true)
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