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replace

Examines each element in a range and replaces it if it matches a specified value.

template<class ForwardIterator, class Type>
   void replace(
      ForwardIterator _First, 
      ForwardIterator _Last,
      const Type& _OldVal, 
      const Type& _NewVal
   );

Parameters

  • _First
    A forward iterator pointing to the position of the first element in the range from which elements are being replaced.

  • _Last
    A forward iterator pointing to the position one past the final element in the range from which elements are being replaced.

  • _OldVal
    The old value of the elements being replaced.

  • _NewVal
    The new value being assigned to the elements with the old value.

Remarks

The range referenced must be valid; all pointers must be dereferenceable and within the sequence 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.

Example

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

int main( ) {
   using namespace std;
   vector <int> v1;
   vector <int>::iterator 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( ) );
   cout << "The original vector v1 is:\n ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;

   // Replace elements with a value of 7 with a value of 700
   replace (v1.begin( ), v1.end( ), 7 , 700);

   cout << "The vector v1 with a value 700 replacing that of 7 is:\n ( " ;
   for ( Iter1 = v1.begin( ) ; Iter1 != v1.end( ) ; Iter1++ )
      cout << *Iter1 << " ";
   cout << ")." << endl;
}

Sample Output

The original vector v1 is:
 ( 7 1 9 2 0 7 7 3 4 6 8 5 7 7 ).
The vector v1 with a value 700 replacing that of 7 is:
 ( 700 1 9 2 0 700 700 3 4 6 8 5 700 700 ).

Requirements

Header: <algorithm>

Namespace: std

See Also

Reference

replace (STL Samples)

Standard Template Library

Other Resources

<algorithm> Members