forward_list::unique() is an inbuilt function in C++ STL which removes all consecutive duplicate elements from the forward_list. It uses binary predicate for comparison.
Parameters: The function accepts a single parameter which is a binary predicate that returns true if the elements should be treated as equal. It has following syntax:
bool name(data_type a, data_type a)
Return value: The function does not return anything.
List of elements before unique operation is: 1 1 1 1 2 2 2 2 3 3 3 2 4 4 List of elements after unique operation is: 1 2 3 2 4