unique_copy
copies elements from the range [first, last)
to a range beginning with result
, except that in a consecutive group of duplicate elements only the first one is copied. The return value is the end of the range to which the elements are copied.
The reason there are two different versions of unique_copy is that there are two different definitions of what it means for a consecutive group of elements to be duplicates. In the first version, the test is simple equality: the elements in a range [f, l)
are duplicates if, for every iterator i
in the range, either i == f
or else *i == *(i-1)
. In the second, the test is an arbitrary BinaryPredicate
binary_pred:
the elements in [f, l)
are duplicates if, for every iterator i
in the range, either i == f
or else binary_pred(*i, *(i-1))
is true
.
This version of unique_copy
uses operator==
to test for equality.
- Parameters
-
first | The beginning of the input range. |
last | The end of the input range. |
result | The beginning of the output range. |
- Returns
- The end of the unique range
[result, result_end)
.
- Template Parameters
-
- Precondition
- The range
[first,last)
and the range [result, result + (last - first))
shall not overlap.
The following code snippet demonstrates how to use unique_copy
to compact a sequence of numbers to remove consecutive duplicates.
...
const int N = 7;
int A[N] = {1, 3, 3, 3, 2, 2, 1};
int B[N];
- See also
- unique
-
https://en.cppreference.com/w/cpp/algorithm/unique_copy