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2010-05-25T10:30:44Z

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==Replace values in vector with another value with replace()==

<source lang="cpp">#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
bool greater9( int );
int main()
{
const int SIZE = 10;
int a[ SIZE ] = { 10, 2, 10, 4, 16, 6, 14, 8, 12, 10 };
// Replace 10s in v1 with 100
vector< int > v1( a, a + SIZE );
replace( v1.begin(), v1.end(), 10, 100 );
return 0;
}
bool greater9( int x ){
return x > 9;
}</source>

==Use replace to replace all elements with value 6 with 42==

<source lang="cpp">/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
}
/* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
}
using namespace std;
int main()
{
list<int> coll;
INSERT_ELEMENTS(coll,2,7);
INSERT_ELEMENTS(coll,4,9);
PRINT_ELEMENTS(coll,"coll: ");
// replace all elements with value 6 with 42
replace (coll.begin(), coll.end(), // range
6, // old value
42); // new value
PRINT_ELEMENTS(coll,"coll: ");
}</source>
<pre class=codeResult>coll: 2 3 4 5 6 7 4 5 6 7 8 9
coll: 2 3 4 5 42 7 4 5 42 7 8 9</pre>

==Use replace to replace all elements with value less than 5 with 0==

<source lang="cpp">/* The following code example is taken from the book
* "The C++ Standard Library - A Tutorial and Reference"
* by Nicolai M. Josuttis, Addison-Wesley, 1999
*
* (C) Copyright Nicolai M. Josuttis 1999.
* Permission to copy, use, modify, sell and distribute this software
* is granted provided this copyright notice appears in all copies.
* This software is provided "as is" without express or implied
* warranty, and with no claim as to its suitability for any purpose.
*/
#include <iostream>
#include <vector>
#include <deque>
#include <list>
#include <set>
#include <map>
#include <string>
#include <algorithm>
#include <iterator>
#include <functional>
#include <numeric>
/* PRINT_ELEMENTS()
* - prints optional C-string optcstr followed by
* - all elements of the collection coll
* - separated by spaces
*/
template <class T>
inline void PRINT_ELEMENTS (const T& coll, const char* optcstr="")
{
typename T::const_iterator pos;
std::cout << optcstr;
for (pos=coll.begin(); pos!=coll.end(); ++pos) {
std::cout << *pos << " ";
}
std::cout << std::endl;
}
/* INSERT_ELEMENTS (collection, first, last)
* - fill values from first to last into the collection
* - NOTE: NO half-open range
*/
template <class T>
inline void INSERT_ELEMENTS (T& coll, int first, int last)
{
for (int i=first; i<=last; ++i) {
coll.insert(coll.end(),i);
}
}
using namespace std;
int main()
{
list<int> coll;
INSERT_ELEMENTS(coll,2,7);
INSERT_ELEMENTS(coll,4,9);
PRINT_ELEMENTS(coll,"coll: ");
// replace all elements with value less than 5 with 0
replace_if (coll.begin(), coll.end(), // range
bind2nd(less<int>(),5), // criterion for replacement
0); // new value
PRINT_ELEMENTS(coll,"coll: ");
}</source>
<pre class=codeResult>coll: 2 3 4 5 6 7 4 5 6 7 8 9
coll: 0 0 0 5 6 7 0 5 6 7 8 9</pre>

==Use replace() to replace elements in a vector==

<source lang="cpp">#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
template<class InIter>
void show_range(const char *msg, InIter start, InIter end);
int main()
{
vector<char> v;
vector<char>::iterator itr, itr_end;
for(int i=0; i<5; i++) {
v.push_back("A"+i);
}
for(int i=0; i<5; i++) {
v.push_back("A"+i);
}
show_range("Original contents of v:", v.begin(), v.end());

// Replace B"s with X"s
replace(v.begin(), v.end(), "B", "X");
show_range("v after replacing B with X:", v.begin(), itr_end);
return 0;
}
template<class InIter>
void show_range(const char *msg, InIter start, InIter end) {
InIter itr;
cout << msg << endl;
for(itr = start; itr != end; ++itr){
cout << *itr << endl;
}
}</source>

==Use std::replace to replace elements in vector by value==

<source lang="cpp">#include <iostream>
using std::cout;
using std::endl;
#include <algorithm>
#include <vector>
#include <iterator>
int main()
{
int a[ 10 ] = { 10, 2, 10, 4, 16, 6, 14, 8, 12, 10 };
std::ostream_iterator< int > output( cout, " " );
std::vector< int > v1( a, a + 10 ); // copy of a
cout << "Vector v1 before replacing all 10s:\n ";
std::copy( v1.begin(), v1.end(), output );
// replace all 10s in v1 with 100
std::replace( v1.begin(), v1.end(), 10, 100 );
cout << "\nVector v1 after replacing 10s with 100s:\n ";
std::copy( v1.begin(), v1.end(), output );
cout << endl;
return 0;
}</source>
<pre class=codeResult>Vector v1 before replacing all 10s:
10 2 10 4 16 6 14 8 12 10
Vector v1 after replacing 10s with 100s:
100 2 100 4 16 6 14 8 12 100</pre>

==Use the generic replace algorithm to replace all occurrences of R by S==

<source lang="cpp">#include <iostream>
#include <cassert>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;
int main()
{
string s("FERRARI");
vector<char> vector1(s.begin(), s.end());

replace(vector1.begin(), vector1.end(), "R", "S");
for(int i=0;i<vector1.size();i++){
cout << vector1[i] << " ";
}
return 0;
}</source>
<pre class=codeResult>F E S S A S I</pre>

==Using "std::replace" to replace value 5 by 8==

<source lang="cpp">#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
// The unary predicate used by replace_if to replace even numbers
bool IsEven (const int & nNum){
return ((nNum % 2) == 0);
}
int main ()
{
// Initialize a sample vector with 6 elements
vector <int> v (6);
// fill first 3 elements with value 8
fill (v.begin (), v.begin () + 3, 8);
// fill last 3 elements with value 5
fill_n (v.begin () + 3, 3, 5);
for (size_t nIndex = 0; nIndex < v.size (); ++ nIndex){
cout << "Element [" << nIndex << "] = ";
cout << v [nIndex] << endl;
}
cout << endl << "Using "std::replace" to replace value 5 by 8" << endl;
replace (v.begin (), v.end (), 5, 8);
for (size_t nIndex = 0; nIndex < v.size (); ++ nIndex){
cout << "Element [" << nIndex << "] = ";
cout << v [nIndex] << endl;
}
return 0;
}</source>

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