C++ Tutorial/STL Algorithms Modifying sequence operations/remove copy

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Copy from one vector to another and remove values with remove_copy()

#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 };
   // Remove 10 from v
   vector< int > v( a, a + SIZE );
   vector< int >::iterator newLastElement;
   newLastElement = remove( v.begin(), v.end(), 10 );
   // Copy from v2 to c, removing 10s
   vector< int > v2( a, a + SIZE );
   vector< int > c( SIZE, 0 );
   remove_copy( v2.begin(), v2.end(), c.begin(), 10 );
   return 0;
}
bool greater9( int x )
{
   return x > 9;
}

std::remove_copy

#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 > v2( a, a + 10 ); // copy of a
   std::vector< int > c( 10, 0 ); // instantiate vector c
   cout << "Vector v2 before removing all 10s and copying:\n   ";
   std::copy( v2.begin(), v2.end(), output );
   // copy from v2 to c, removing 10s in the process
   std::remove_copy( v2.begin(), v2.end(), c.begin(), 10 );
   cout << "\nVector c after removing all 10s from v2:\n   ";
   std::copy( c.begin(), c.end(), output );
   return 0;
}
Vector v2 before removing all 10s and copying:
   10 2 10 4 16 6 14 8 12 10
Vector c after removing all 10s from v2:
   2 4 16 6 14 8 12 0 0 0

Use remove_copy to delete all space in a char array

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
   
int main()
{
  char str[] = "This is a test.";
  vector<char> v, v2(30);
  unsigned int i;
   
  for(i=0; str[i]; i++) v.push_back(str[i]);
   
  for(i=0; i<v.size(); i++) cout << v[i];
   
  // remove all spaces
  remove_copy(v.begin(), v.end(), v2.begin(), " ");
   
  cout << "Result after removing spaces:\n";
  for(i=0; i<v2.size(); i++) cout << v2[i];
  cout << endl << endl;
   
  return 0;
}

Use remove_copy to print elements without those having the value 3

/* 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> coll1;
    INSERT_ELEMENTS(coll1,1,6);
    INSERT_ELEMENTS(coll1,1,9);
    PRINT_ELEMENTS(coll1);
    // print elements without those having the value 3
    remove_copy(coll1.begin(), coll1.end(),       // source
                ostream_iterator<int>(cout," "),  // destination
                3);                               // removed value
    cout << endl;
}
1 2 3 4 5 6 1 2 3 4 5 6 7 8 9
1 2 4 5 6 1 2 4 5 6 7 8 9

Use remove_copy with vector

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
   
int main()
{
  char str[] = "This is a test.";
  vector<char> v, v2(30);
  unsigned int i;
   
  for(i=0; str[i]; i++) v.push_back(str[i]);
   
  for(i=0; i<v.size(); i++) {
     cout << v[i] << endl;
  }
  
  remove_copy(v.begin(), v.end(), v2.begin(), " ");
   
  for(i=0; i<v2.size(); i++) cout << v2[i];
  cout << endl << endl;
  
  return 0;
}