The first version traverses the sequence [ first ... last ) and stores the results of invoking op on each element into a sequence of the same size starting at result . The second version uses a pair of iterators i and j to traverse two sequences, starting at first1 and first2 , respectively, until i reaches last1 . The second version stores the results of invoking binary_op on the elements referenced by the iterator pair into a sequence of the same size starting at result . Both versions return an iterator positioned immediately after the last new element.

Declaration


  
#include <algorithm>

template
  <
  class InputIterator,
  class OutputIterator,
  class UnaryOperation
  >
OutputIterator transform
  (
  InputIterator first,
  InputIterator last,
  OutputIterator result,
  UnaryOperation op
  );

template
  <
  class InputIterator1,
  class InputIterator2,
  class OutputIterator,
  class BinaryOperation
  >
OutputIterator transform
  (
  InputIterator1 first1,
  InputIterator1 last1,
  InputIterator2 first2,
  OutputIterator result,
  BinaryOperation binary_op
  );

Complexity

Time complexity is linear, as ( last1 - first1 ) operations are performed. Space complexity is constant.

Example <ospace/osstd/examples/trnsfrm1.cpp>


    #include <iostream>
#include <algorithm>

int numbers[ 6 ] = { -5, -1, 0, 1, 6, 11 };

int
negate_int( int a_ )
  {
  return -a_;
  }

void
main()
  {
  int result[ 6 ];

  transform
    (
    numbers,
    numbers + 6,
    result,
    negate_int
    );

  for ( int i = 0; i < 6; ++i )
    cout << result[ i ] << ` `;
  cout << "\n";
  }

5 1 0 -1 -6 -11

Example <ospace/osstd/examples/trnsfrm2.cpp>


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

int trans[] = {-4, 4, -6, -6, -10, 0, 10, -6, 6, 0, -1, -77};
char n[] = "Larry Mullen";

char
map_char( char a_, int b_ )
  {
  return char( a_ + b_ );
  }

void
main()
  {
  const unsigned count = ::strlen( n );
  ostream_iterator< char > iter( cout );

  transform( n, n + count, trans, iter, map_char );

  cout << "\n";
  }

Hello World!

transform

Library

Declaration

Complexity

Example <ospace/osstd/examples/trnsfrm1.cpp>

Example <ospace/osstd/examples/trnsfrm2.cpp>