The sample code below illustrates how to use the count STL function in
Visual C++.
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Required Header
<algorithm>
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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.
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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.
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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
#pragma warning(disable: 4786)
#include <iostream>
#include <algorithm>
#include <functional>
#include <string>
#include <vector>
using namespace std;
void main()
{
const int VECTOR_SIZE = 8 ;
// Define a template class vector of strings
typedef vector<string, allocator<string> > 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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Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library
Reference.
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