Standard C++ Library
Copyright 1998, Rogue Wave Software, Inc.
NAME
replace_copy_if
- Substitutes elements in a collection with new values, and
moves the revised sequence into result.
SYNOPSIS
#include <algorithm>
template <class InputIterator,
class OutputIterator,
class Predicate,
class T>
OutputIterator replace_copy_if (InputIterator first,
InputIterator last,
OutputIterator result,
Predicate pred,
const T& new_value);
DESCRIPTION
The replace_copy_if algorithm leaves the original sequence
intact and places a revised sequence into result. For the
range [first,last), the algorithm compares each element *i
with the conditions specified by pred. If pred(*i)==false,
replace_copy_if copies *i to result+(first-i). If
pred(*i)==true, then replace_copy copies new_value to
result+(first-i). replace_copy_if_returns result+(last-
first).
COMPLEXITY
Exactly last - first applications of the predicate are per-
formed.
EXAMPLE
//
// replace.cpp
//
#include <algorithm>
#include <vector>
#include <iterator>
#include <iostream>
using namespace std;
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,char>(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,char>(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,char>(cout," "));
cout << endl << endl;
//
// Replace those 13s with 17s on output.
//
cout << "List using replace_copy to cout:" << endl
<< " ";
replace_copy(v.begin(), v.end(),
ostream_iterator<int,char>(cout, " "),
13, 17);
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(), <br>
ostream_iterator<int,char>(cout, " "),
all_true<int>(), 19);
cout << endl;
return 0;
}
Program 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
WARNINGS
If your compiler does not support default template parame-
ters, then you always need to supply the Allocator template
argument. For instance, you need to write:
vector<int, allocator<int> >
instead of:
vector<int>
If your compiler does not support namespaces, then you do
not need the using declaration for std.
SEE ALSO
replace, replace_if, replace_copy