C++/STL Algorithms Modifying sequence operations/replace copy if

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std::replace_copy_if with predicate

<source lang="cpp">


  1. include <iostream>

using std::cout; using std::endl;

  1. include <algorithm>
  2. include <vector>
  3. include <iterator>

bool greater9( int ); int main() {

  int a[ 10 ] = { 10, 2, 10, 4, 16, 6, 14, 8, 12, 10 };
  std::ostream_iterator< int > output( cout, " " );
  std::vector< int > v4( a, a + 10 ); // copy of a
  std::vector< int > c2( 10 ); // instantiate vector c2
  cout << "Vector v4 before replacing all values greater than 9 and copying:\n;
  std::copy( v4.begin(), v4.end(), output );
  // copy v4 to c2, replacing elements greater than 9 with 100
  std::replace_copy_if(v4.begin(), v4.end(), c2.begin(), greater9, 100 );
  cout << "\nVector c2 after replacing all values greater than 9 in v4:\n   ";
  std::copy( c2.begin(), c2.end(), output );
  cout << endl;
  return 0;

} bool greater9( int x ) {

  return x > 9;

} /* Vector v4 before replacing all values greater than 9 and copying: 10 2 10 4 16 6 14 8 12 10 Vector c2 after replacing all values greater than 9 in v4:

  100 2 100 4 100 6 100 8 100 100
*/        
 </source>


Use replace_copy_if to print all elements with a value less than 5 replaced 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.
*/
  1. include <iostream>
  2. include <vector>
  3. include <deque>
  4. include <list>
  5. include <set>
  6. include <map>
  7. include <string>
  8. include <algorithm>
  9. include <iterator>
  10. include <functional>
  11. 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,2,6);
   INSERT_ELEMENTS(coll,4,9);
   PRINT_ELEMENTS(coll);
   // print all elements with a value less than 5 replaced with 42
   replace_copy_if(coll.begin(), coll.end(),        // source
                   ostream_iterator<int>(cout," "), // destination
                   bind2nd(less<int>(),5),     // replacement criterion
                   42);                        // new value
   cout << endl;

}

/* 

2 3 4 5 6 4 5 6 7 8 9 42 42 42 5 6 42 5 6 7 8 9

*/       
 </source>


Use replace_copy_if to print each element while each odd element is replaced 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.
*/
  1. include <iostream>
  2. include <vector>
  3. include <deque>
  4. include <list>
  5. include <set>
  6. include <map>
  7. include <string>
  8. include <algorithm>
  9. include <iterator>
  10. include <functional>
  11. 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,2,6);
   INSERT_ELEMENTS(coll,4,9);
   PRINT_ELEMENTS(coll);
   // print each element while each odd element is replaced with 0
   replace_copy_if(coll.begin(), coll.end(),        // source
                   ostream_iterator<int>(cout," "), // destination
                   bind2nd(modulus<int>(),2),  // replacement criterion
                   0);                         // new value
   cout << endl;

} /* 2 3 4 5 6 4 5 6 7 8 9 2 0 4 0 6 4 0 6 0 8 0

*/
       
 </source>