.\" ident @(#)replace.3
.\" Standard Template Library
.\" $$RW_INSERT_HEADER "slyrs.man"
.TH replace 3C++ "02 Apr 1998" "Rogue Wave Software" "-"
.ce2
Standard C++ Library   
Copyright 1998, Rogue Wave Software, Inc.   

.SH NAME

\f2replace\fP

\ - Substitutes elements in a collection with new values.



.SH  SYNOPSIS


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#include <algorithm>
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template <class ForwardIterator, class T>
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void replace (ForwardIterator first,
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ForwardIterator last,
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const T& old_value,
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const T& new_value);



.SH  DESCRIPTION


For the range \f2[first, last)\fP, the replace algorithm replaces elements referred to by iterator \f2i\fP with \f2new_value\fP, when the following condition holds: \f2*i == old_value\fP.



.SH  COMPLEXITY


Exactly \f2last - first\fP comparisons or applications of the corresponding predicate are done.



.SH  EXAMPLE



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//
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// replace.cpp
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//
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#include <algorithm>
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#include <vector>
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#include <iterator>
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#include <iostream>
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using namespace std;
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template<class Arg>
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struct all_true : public unary_function<Arg, bool>
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{
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bool operator()(const Arg&){ return 1; }
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};
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int main()
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{
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//Initialize a vector with an array of integers
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int arr[10] = {1,2,3,4,5,6,7,8,9,10};
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vector<int> v(arr, arr+10);
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//Print out original vector
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cout << "The original list: " << endl << "     ";
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copy(v.begin(),v.end(),ostream_iterator<int,char>
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(cout," "));
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cout << endl << endl;
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//Replace the number 7 with 11
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replace(v.begin(), v.end(), 7, 11);
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// Print out vector with 7 replaced, 
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// s.b. 1 2 3 4 5 6 11 8 9 10
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cout << "List after replace " << endl << "     ";
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copy(v.begin(),v.end(),o
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stream_iterator<int,char>(cout," "));
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cout << endl << endl;
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//Replace 1 2 3 with 13 13 13
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replace_if(v.begin(), v.begin()+3, all_true<int>(), 13);
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// Print out the remaining vector, 
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// s.b. 13 13 13 4 5 6 11 8 9 10
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cout << "List after replace_if " << endl << "     ";
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copy(v.begin(),v.end(),
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ostream_iterator<int,char>(cout," "));
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cout << endl << endl;
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return 0;
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}

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Program Output



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The original list:
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1 2 3 4 5 6 7 8 9 10
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List after replace:
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1 2 3 4 5 6 11 8 9 10
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List after replace_if:
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13 13 13 4 5 6 11 8 9 10
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List using replace_copy to cout:
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17 17 17 4 5 6 11 8 9 10
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List with all elements output as 19s:
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19 19 19 19 19 19 19 19 19 19



.SH  WARNINGS


If your compiler does not support default template parameters, then you always need to supply the \f2Allocator\fP template argument. For instance, you need to write:

\f2vector<int, allocator<int> >\fP

instead of:

\f2vector<int>\fP

If your compiler does not support namespaces, then you do not need the using declaration for \f2std\fP.



.SH  SEE ALSO


replace_if, replace_copy, replace_copy_if