
unique (3C++std)  Tru64 UNIX
Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc. NAME
unique, unique_copy  Removes consecutive duplicates from a range of
values and places the resulting unique values into the result.
SYNOPSIS
#include <algorithm>
template <class ForwardIterator>
ForwardIterator unique (ForwardIterator first,
ForwardIterator last);
template <class ForwardIterator, class BinaryPredicate>
ForwardIterator unique (ForwardIterator first,
ForwardIterator last,
BinaryPredicate binary_pred);
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);
DESCRIPTION
The unique algorithm moves through a sequence and eliminates all but the
first element from every consecutive group of equal elements. There are
two versions of the algorithm, one tests for equality, and the other tests
whether a binary predicate applied to adjacent elements is true. An
element is unique if it does not meet the corresponding condition listed
here:
*i == *(i  1)
or
binary_pred(*i, *(i  1)) == true.
If an element is unique, it is copied to the front of the sequence,
overwriting the existing elements. Once all unique elements have been
identified. The remainder of the sequence is left unchanged, and unique
returns the end of the resulting range.
The unique_copy algorithm copies the first element from every consecutive
group of equal elements, to an OutputIterator. The unique_copy algorithm,
also has two versionsone that tests for equality and a second that tests
adjacent elements against a binary predicate.
unique_copy returns the end of the resulting range.
COMPLEXITY
Exactly (last  first)  1 applications of the corresponding predicate are
performed.
EXAMPLE
//
// unique.cpp
//
#include <algorithm>
#include <vector>
#include <iostream.h>
int main()
{
//Initialize two vectors
int a1[20] = {4, 5, 5, 9, 1, 1, 1, 3, 7, 5,
5, 5, 6, 7, 7, 7, 4, 2, 1, 1};
vector<int> v(a1, a1+20), result;
//Create an insert_iterator for results
insert_iterator<vector<int> > ins(result,
result.begin());
//Demonstrate includes
cout << "The vector: " << endl << " ";
copy(v.begin(),v.end(),ostream_iterator<int,char>(cout," "));
//Find the unique elements
unique_copy(v.begin(), v.end(), ins);
//Display the results
cout << endl << endl
<< "Has the following unique elements:"
<< endl << " ";
copy(result.begin(),result.end(),
ostream_iterator<int,char>(cout," "));
return 0;
}
Output :
The vector:
4 5 5 9 1 1 1 3 7 5 5 5 6 7 7 7 4 2 1 1
Has the following unique elements:
4 5 9 1 3 7 5 6 7 4 2 1
WARNING
If your compiler does not support default template parameters, then you
need to always supply the Allocator template argument. For instance, you
will need to write :
vector<int, allocator<int> >
instead of:
vector<int>
STANDARDS CONFORMANCE
ANSI X3J16/ISO WG21 Joint C++ Committee
