Microsoft KB Archive/156618

= STL Sample for the count Function =

Article ID: 156618

Article Last Modified on 12/2/2003

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APPLIES TO

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

 Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 5.0 Learning Edition 

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This article was previously published under Q156618

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

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Prototype
template<class InputIterator, class T> inline </WWFIXEDTEXT> <WWBLOCKQUOTE> template<class InputIterator, class T> inline size_t count(InputIterator first,                                       InputIterator last,                                        const T& value) NOTE: The class/parameter names in the prototype do not match the version in the header file. Some have been modified to improve readability.

Description
The count algorithm counts the number of elements in the range [first, last +1) that match value and returns the number of matching elements.

Sample Code
////////////////////////////////////////////////////////////////////// // // Compile options needed: /GX // // count.cpp : Illustrates how to use the count function. // // Functions: // //   count  - Count items in a range that match a value. // // Written by Kalindi Sanghrajka // of Microsoft Product Support Services, // Software Core Developer Support. // Copyright (c) 1996 Microsoft Corporation. All rights reserved. //////////////////////////////////////////////////////////////////////

// disable warning C4786: symbol greater than 255 character, // okay to ignore
 * 1) pragma warning(disable: 4786)

using namespace std;
 * 1) include
 * 2) include
 * 3) include
 * 4) include
 * 5) include

void main {   const int VECTOR_SIZE = 8 ;

// Define a template class vector of strings typedef vector<string, allocator > StringVector ;

//Define an iterator for template class vector of strings typedef StringVector::iterator StringVectorIt ;

StringVector NamesVect(VECTOR_SIZE) ;  //vector containing names

string value("Sea") ; // stores the value used // to count matching elements

StringVectorIt start, end, it ;

int result = 0 ;  // stores count of elements // that match value.

// Initialize vector NamesVect NamesVect[0] = "She" ; NamesVect[1] = "Sells" ; NamesVect[2] = "Sea" ; NamesVect[3] = "Shells" ; NamesVect[4] = "by" ; NamesVect[5] = "the" ; NamesVect[6] = "Sea" ; NamesVect[7] = "Shore" ;

start = NamesVect.begin ;  // location of first // element of NamesVect

end = NamesVect.end ;      // one past the location // last element of NamesVect

// print content of NamesVect cout << "NamesVect { " ; for(it = start; it != end; it++) cout << *it << " " ; cout << " }\n" << endl ;

// Count the number of elements in the range [first, last +1)   // that match value.    result = count(start, end, value) ;

// print the count of elements that match value cout << "Number of elements that match \"Sea\" = " << result << endl ; } Program Output is:

NamesVect { She Sells Sea Shells by the Sea Shore }

Number of elements that match "Sea" = 2

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