Microsoft KB Archive/158574

= How to use the set::count STL function in Visual C++ =

Article ID: 158574

Article Last Modified on 1/11/2006

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APPLIES TO

 The Standard C++ Library, when used with:  Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 5.0 Enterprise Edition

 Microsoft Visual C++ 6.0 Enterprise Edition

 Microsoft Visual C++ 4.2 Professional Edition</li></ul>

 Microsoft Visual C++ 5.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Professional Edition</li></ul>

 Microsoft Visual C++ 6.0 Standard Edition</li></ul>

 Microsoft Visual C++ 2005 Express Edition</li></ul>

 Microsoft Visual C++ .NET 2003 Standard Edition</li></ul>

 Microsoft Visual C++ .NET 2002 Standard Edition</li></ul> </li></ul>

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This article was previously published under Q158574

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Note Microsoft Visual C++ .NET 2002 and Microsoft Visual C++ .NET 2003 support both the managed code model that is provided by the Microsoft .NET Framework and the unmanaged native Microsoft Windows code model. The information in this article applies only to unmanaged Visual C++ code. Microsoft Visual C++ 2005 supports both the managed code model that is provided by the Microsoft .NET Framework and the unmanaged native Microsoft Windows code model.

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SUMMARY
The following sample code illustrates how to use the set::count STL function in Visual C++.

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Prototype
template<class _K, class _Pr, class _A> class set { public: // Function 1:

size_type count(const _K& _Kv) 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.

Description
The count function is used to determine the number of elements in the controlled sequence that have a particular key.

Sample Code
NOTE: The first line in the sample code section says:

// Compile options needed: /GX

In Visual C++ .NET and in Visual C++ 2005, /EHsc is set by default and is equivalent to /GX. ////////////////////////////////////////////////////////////////////// // // Compile options needed: -GX // // SetCount.cpp: //     Illustrates how to use the count function to determine how //     many elements have a particular key. // // Functions: // //   count        Returns the number of elements in the controlled //                sequence that have a particular key. // // Written by Derek Jamison // of Microsoft Technical Support, // Copyright (c) 1996 Microsoft Corporation. All rights reserved. //////////////////////////////////////////////////////////////////////


 * 1) pragma warning(disable:4786)

// disable warning C4267: possible loss of data, // okay to ignore


 * 1) pragma warning(disable: 4267)


 * 1) include
 * 2) include

using namespace std; // std c++ libs implemented in std #endif
 * 1) if _MSC_VER > 1020  // if VC++ version is > 4.2

typedef set<int,less ,allocator > SET_INT;

void truefalse(int x)

{ cout << (x?"True":"False") << endl; }

void main {

SET_INT s1; SET_INT::_Pairib pib; cout << "s1.insert(5)" << endl; pib=s1.insert(5); cout << "Inserted element: "; truefalse(pib.second); // True

cout << "s1.insert(5)" << endl; pib=s1.insert(5); cout << "Inserted element: "; truefalse(pib.second); // True

cout << "s1.insert(8)" << endl; s1.insert(8);

cout << "s1.insert(12)" << endl; s1.insert(12);

cout << "s1.count(5) returned "; cout << s1.count(5) << endl;   // 1

cout << "s1.count(9) returned "; cout << s1.count(9) << endl;   // 0 }

Program Output
s1.insert(5) Inserted element: True s1.insert(5) Inserted element: False s1.insert(8) s1.insert(12) s1.count(5) returned 1 s1.count(9) returned 0

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