Copy the sequence [ first ... last ) to a sequence starting at result , replacing all consecutive occurrences of a value by a single instance of that value. Return an iterator positioned immediately after the last element of the new sequence. The first version uses operator== to determine equality, whereas the second version uses the binary function binary_pred .

Declaration


  
#include <algorithm>

template< class InputIterator, class OutputIterator >
OutputIterator unique_copy
  (
  InputIterator first,
  InputIterator last,
  OutputIterator result
  );

template< class InputIterator, class OutputIterator,

class BinaryPredicate >
OutputIterator unique_copy
  (
  InputIterator first,
  InputIterator last,
  OutputIterator result,
  BinaryPredicate binary_pred
  );

Complexity

Time complexity is linear, as ( last - first ) operations are performed. Space complexity is constant.

Example <ospace/osstd/examples/uniqcpy1.cpp>


    #include <iostream>
#include <algorithm>

int numbers[ 8 ] = { 0, 1, 1, 2, 2, 2, 3, 4 };
int result[ 8 ] = { 0, 0, 0, 0, 0, 0, 0, 0 };

void
main()
  {
  unique_copy( numbers, numbers + 8, result );

  for ( int i = 0; i < 8; ++i )
    cout << result[ i ] << ` `;
  cout << "\n";
  }

0 1 2 3 4 0 0 0

Example <ospace/osstd/examples/uniqcpy2.cpp>


    #include <iostream>
#include <string.h>
#include <algorithm>

const char* labels[] = { "Q","Q","W","W","E","E","R","T","T","Y","Y" };

bool
str_equal( const char* a_, const char* b_ )
  {
  return ::strcmp( a_, b_ ) == 0 ? 1 : 0;
  }

void
main()
  {
  const unsigned count = sizeof( labels ) / sizeof( labels[ 0 ] );
  ostream_iterator< const char* > iter( cout );
  copy( labels, labels + count, iter );
  cout << "\n";
  const char* u_copy[ count ];
  fill (u_copy, u_copy + count, "" );

  unique_copy( labels, labels + count, u_copy, str_equal );

  copy( labels, labels + count, iter );
  cout << "\n";
  copy( u_copy, u_copy + count, iter );
  cout << "\n";
  }

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unique_copy

Library

Declaration

Complexity

Example <ospace/osstd/examples/uniqcpy1.cpp>

Example <ospace/osstd/examples/uniqcpy2.cpp>