INFO: STL Sample for the partial_sum Function (157393)
The information in this article applies to:
- The Standard C++ Library, when used with:
- Microsoft Visual C++, 32-bit Enterprise Edition 4.2
- Microsoft Visual C++, 32-bit Enterprise Edition 5.0
- Microsoft Visual C++, 32-bit Enterprise Edition 6.0
- Microsoft Visual C++, 32-bit Professional Edition 4.2
- Microsoft Visual C++, 32-bit Professional Edition 5.0
- Microsoft Visual C++, 32-bit Professional Edition 6.0
- Microsoft Visual C++, 32-bit Learning Edition 6.0
- Microsoft Visual C++ .NET (2003)
- Microsoft Visual C++ .NET (2002)
This article was previously published under Q157393 NOTE: Microsoft Visual C++ NET (2002) supported both the managed code
model that is provided by the .NET Framework and the unmanaged native Windows
code model. The information in this article applies to unmanaged Visual C++
code only. SUMMARY The sample code below illustrates how to use partial_sum
STL function in Visual C++. MORE INFORMATIONRequired Header
#include <numeric>
#include <functional>
Prototype
template<class InputIterator, class OutputIterator> inline
OutputIterator partial_sum(InputIterator first, InputIterator last,
OutputIterator first2)
template<class InputIterator, class OutputIterator,
class BinaryOperator> inline
OutputIterator partial_sum(InputIterator first, InputIterator last,
OutputIterator first2,
BinaryOperator binary_op)
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 Assigns to every iterator i in the range [result,result + (last -
first)) a value correspondingly equal to ((...(*first + *(first + 1)) + ...) +
*(first + (i - result))) binary_op(binary_op(..., binary_op(*first, *(first + 1)),...),
*(first + (i - result))) In other words, *(result+i) = init +
*(first+0) + *(first+1) + ... + *(first+i) Sample Code
///////////////////////////////////////////////////////////////////////
//
// Compile options needed: /GX
//
// partial_sum.cpp : Demonstrates the use of partial_sum().
//
// Description of partial_sum(first,last,first2,init)
// partial_sum(first,last,first2,init,binary_op):
//
// Assigns to every iterator i in the range
// [result,result + (last - first)) a value correspondingly equal to
// ((...(*first + *(first + 1)) + ...) + *(first + (i - result)))
//
// - or -
//
// binary_op(binary_op(..., binary_op(*first, *(first + 1)),...),
// *(first + (i - result)))
//
// In other words,
// *(result+i) = init + *(first+0) + *(first+1) + ... + *(first+i)
//
// Written by Shaun Miller
// of Microsoft Product Support Services, Languages Developer Support.
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
///////////////////////////////////////////////////////////////////////
#include <iostream>
#include <numeric>
#include <functional>
#include <vector>
#include <iterator>
#if _MSC_VER > 1020 // if VC++ version is > 4.2
using namespace std; // std c++ libs implemented in std
#endif
typedef vector < int, allocator < int > > IntArray;
typedef ostream_iterator < int, char, char_traits<char> > IntOstreamIt;
void main ()
{
IntOstreamIt itOstream(cout," ");
// Initialize the array
IntArray rgI;
for (int i=1; i<=10; i++) rgI.push_back(i);
// Print the arrays
cout << "Array: ";
copy(rgI.begin(),rgI.end(),itOstream);
cout << endl;
// The result array must be at least the same size as the data array
IntArray rgIresult(rgI.size());
// Compute the partial sum of the array
partial_sum(rgI.begin(),rgI.end(),rgIresult.begin());
// Print the array of partial sums
cout << "Array of partial sums: ";
copy(rgIresult.begin(),rgIresult.end(),itOstream);
cout << endl;
// Compute the partial product of the array
partial_sum(rgI.begin(),rgI.end(),rgIresult.begin(),multiplies<int>());
// Print the array of partial products
cout << "Array of partial products: ";
partial_sum(rgIresult.begin(),rgIresult.end(),itOstream);
cout << endl;
}
The program output is:
Array: 1 2 3 4 5 6 7 8 9 10
Array of partial sums: 1 3 6 10 15 21 28 36 45 55
Array of partial products: 1 3 9 33 153 873 5913 46233 409113 4037913
REFERENCES
Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library
Reference.
Modification Type: | Major | Last Reviewed: | 9/22/2003 |
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Keywords: | kbcode kbinfo KB157393 |
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