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<P>©Copyright 1996 Rogue Wave Software</P>
<H2>replace</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 ForwardIterator, class T>
void <B>replace</B> (ForwardIterator first,
ForwardIterator last,
const T& old_value,
const T& new_value);
</PRE>
<A NAME="Description"><H3>Description</H3></A>
<P>The <B><I>replace</B></I> algorithm replaces elements referred to by iterator <SAMP>i</SAMP> in the range <SAMP>[first, last)</SAMP> with <SAMP>new_value</SAMP> when the following condition holds: <SAMP>*i == old_value</SAMP> </P>
<A NAME="Complexity"><H3>Complexity</H3></A>
<P>Exactly <SAMP>last - first</SAMP> comparisons or applications of the corresponding predicate 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, 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
<B>replace</B>(v.begin(), v.end(), 7, 11);
// Print out vector with 7 replaced,
// s.b. 1 2 3 4 5 6 11 8 9 10
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,
// s.b. 13 13 13 4 5 6 11 8 9 10
cout << "List after replace_if " << endl << " ";
copy(v.begin(),v.end(),ostream_iterator<int>(cout," "));
cout << endl << 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_6837.htm"><B><I>replace_if</B></I></A>, <A HREF="rep_5264.htm"><B><I>replace_copy</B></I></A>, <A HREF="rep_8915.htm"><B><I>replace_copy_if</B></I></A></P>
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