replace_copy

Article
07/29/2015

Examines each element in a source range and replaces it if it matches a specified value while copying the result into a new destination range.

template<class InputIterator, class OutputIterator, class Type> 
   OutputIterator replace_copy( 
      InputIterator _First,  
      InputIterator _Last,  
      OutputIterator _Result, 
      const Type& _OldVal,  
      const Type& _NewVal 
   );

Parameters

_First
An input iterator pointing to the position of the first element in the range from which elements are being replaced.
_Last
An input iterator pointing to the position one past the final element in the range from which elements are being replaced.
_Result
An output iterator pointing to the first element in the destination range to where the altered sequence of elements is being copied.
_OldVal
The old value of the elements being replaced.
_NewVal
The new value being assigned to the elements with the old value.

Return Value

An output iterator pointing to the position one past the final element in the destination range to where the altered sequence of elements is being copied.

Remarks

The source and destination ranges referenced must not overlap and must both be valid: all pointers must be dereferenceable and within the sequences the last position is reachable from the first by incrementation.

The order of the elements not replaced remains stable.

The operator== used to determine the equality between elements must impose an equivalence relation between its operands.

The complexity is linear: there are (_Last – _First) comparisons for equality and at most (_Last – _First) assignments of new values.

replace_copy has two related forms:

For information on how these functions behave, see Checked Iterators.

Example

// alg_replace_copy.cpp
// compile with: /EHsc
#include <vector>
#include <list>
#include <algorithm>
#include <iostream>

int main( ) {
   using namespace std;
   vector <int> v1;
   list <int> L1 (15);
   vector <int>::iterator Iter1;
   list <int>::iterator L_Iter1;

   int i;
   for ( i = 0 ; i <= 9 ; i++ )
      v1.push_back( i );

   int ii;
   for ( ii = 0 ; ii <= 3 ; ii++ )
      v1.push_back( 7 );
   
   random_shuffle ( v1.begin( ), v1.end( ) );

   int iii;
   for ( iii = 0 ; iii <= 15 ; iii++ )
      v1.push_back( 1 );

   cout << "The original vector v1 is:\n ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;

   // Replace elements in one part of a vector with a value of 7
   // with a value of 70 and copy into another part of the vector
   replace_copy ( v1.begin( ), v1.begin( ) + 14,v1.end( ) -15, 7 , 70);

   cout << "The vector v1 with a value 70 replacing that of 7 is:\n ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;

   // Replace elements in a vector with a value of 70
   // with a value of 1 and copy into a list
   replace_copy ( v1.begin( ), v1.begin( ) + 14,L1.begin( ), 7 , 1);

   cout << "The list copy L1 of v1 with the value 0 replacing "
        << "that of 7 is:\n ( " ;
   for ( L_Iter1 = L1.begin( ) ; L_Iter1 != L1.end( ) ; L_Iter1++ )
      cout << *L_Iter1 << " ";
   cout << ")." << endl;
}

Sample Output

The original vector v1 is:
 ( 7 1 9 2 0 7 7 3 4 6 8 5 7 7 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ).
The vector v1 with a value 70 replacing that of 7 is:
 ( 7 1 9 2 0 7 7 3 4 6 8 5 7 7 1 70 1 9 2 0 70 70 3 4 6 8 5 70 70 1 ).
The list copy L1 of v1 with the value 0 replacing that of 7 is:
 ( 1 1 9 2 0 1 1 3 4 6 8 5 1 1 0 ).

Requirements

Header: <algorithm>

Namespace: std

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