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<P>©Copyright 1996 Rogue Wave Software</P>
<H2>replace_copy</H2>
<HR><PRE> Algorithm</PRE><HR>
<A NAME="Summary"><H3>Summary</H3></A>
<P>Substitutes elements stored in a collection with new values.</P>
<H3>Contents</H3>
<UL>
<A HREF="#Synopsis"><LI>Synopsis</LI></A>
<A HREF="#Description"><LI>Description</LI></A>
<A HREF="#Complexity"><LI>Complexity</LI></A>
<A HREF="#Example"><LI>Example</LI></A>
<A HREF="#Warning"><LI>Warning</LI></A>
<A HREF="#See Also"><LI>See Also</LI></A>
</UL>
<A NAME="Synopsis"><H3>Synopsis</H3></A>
<PRE>#include <algorithm></PRE>
<PRE>
template <class InputIterator,
class OutputIterator,
class T>
OutputIterator <B>replace_copy</B> (InputIterator first,
InputIterator last,
OutputIterator result,
const T& old_value,
const T& new_value);
</PRE>
<A NAME="Description"><H3>Description</H3></A>
<P>The <B><I>replace_copy</B></I> algorithm leaves the original sequence intact and places the revised sequence into <SAMP>result</SAMP>. The algorithm compares elements referred to by interator <SAMP>i</SAMP> in the range <SAMP>[first, last)</SAMP> with <SAMP>old_value</SAMP>. If <SAMP>*i </SAMP>does not equal <SAMP>old_value</SAMP>, then the <B><I>replace_copy</B></I> copies <SAMP>*i</SAMP> to <SAMP>result+(first-i)</SAMP>. If <SAMP>*i==old_value</SAMP>, then <B><I>replace_copy</B></I> copies <SAMP>new_value</SAMP> to <SAMP>result+(first-i)</SAMP>. <B><I>replace_copy</B></I> returns <SAMP>result+(last-first)</SAMP>.</P>
<A NAME="Complexity"><H3>Complexity</H3></A>
<P>Exactly <SAMP>last - first</SAMP> comparisons between values are done.</P>
<A NAME="Example"><H3>Example</H3></A>
<PRE>//
// replace.cpp
//
#include <algorithm>
#include <vector>
#include <iterator>
#include <iostream.h>
template<class Arg>
struct all_true : public unary_function<Arg, bool>
{
bool operator() (const Arg&) { return 1; }
};
int main ()
{
//
// Initialize a vector with an array of integers.
//
int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
vector<int> v(arr+0, arr+10);
//
// Print out original vector.
//
cout << "The original list: " << endl << " ";
copy(v.begin(), v.end(), ostream_iterator<int>(cout," "));
cout << endl << endl;
//
// Replace the number 7 with 11.
//
replace(v.begin(), v.end(), 7, 11);
//
// Print out vector with 7 replaced.
//
cout << "List after replace:" << endl << " ";
copy(v.begin(), v.end(), ostream_iterator<int>(cout," "));
cout << endl << endl;
//
// Replace 1 2 3 with 13 13 13.
//
replace_if(v.begin(), v.begin()+3, all_true<int>(), 13);
//
// Print out the remaining vector.
//
cout << "List after replace_if:" << endl << " ";
copy(v.begin(), v.end(), ostream_iterator<int>(cout," "));
cout << endl << endl;
//
// Replace those 13s with 17s on output.
//
cout << "List using replace_copy to cout:" << endl << " ";
<B>replace_copy</B>(v.begin(), v.end(), ostream_iterator<int>(cout, " "), 13, 17);</PRE>
<PRE> cout << endl << endl;
//
// A simple example of replace_copy_if.
//
cout << "List w/ all elements output as 19s:" << endl << " ";
replace_copy_if(v.begin(), v.end(), ostream_iterator<int>(cout, " "),</PRE>
<PRE> all_true<int>(), 19);
cout << endl;
return 0;
}
Output :
The original list:
1 2 3 4 5 6 7 8 9 10
List after replace:
1 2 3 4 5 6 11 8 9 10
List after replace_if:
13 13 13 4 5 6 11 8 9 10
List using replace_copy to cout:
17 17 17 4 5 6 11 8 9 10
List with all elements output as 19s:
19 19 19 19 19 19 19 19 19 19</PRE>
<A NAME="Warning"><H3>Warning</H3></A>
<P>If your compiler does not support default template parameters, then you need to always supply the <SAMP>Allocator</SAMP> template argument. For instance, you will need to write :</P>
<P><SAMP>vector<int, allocator></SAMP></P>
<P>instead of :</P>
<P><SAMP>vector<int></SAMP></P>
<A NAME="See Also"><H3>See Also</H3></A>
<P><A HREF="rep_6131.htm"><B><I>replace</B></I></A>, <A HREF="rep_6837.htm"><B><I>replace_if</B></I></A>, <A HREF="rep_8915.htm"><B><I>replace_copy_if</B></I></A></P>
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