```
template <class InputIterator, class OutputIterator>
OutputIterator
adjacent_difference(InputIterator first, InputIterator last,
OutputIterator result);
template <class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2>
ForwardIterator2
adjacent_difference(ExecutionPolicy&& exec,
ForwardIterator1 first, ForwardIterator1 last,
ForwardIterator2 result);
template <class InputIterator, class OutputIterator, class BinaryOperation>
OutputIterator
adjacent_difference(InputIterator first, InputIterator last,
OutputIterator result,
BinaryOperation binary_op);
template <class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2,
class BinaryOperation>
ForwardIterator2
adjacent_difference(ExecutionPolicy&& exec,
ForwardIterator1 first, ForwardIterator1 last,
ForwardIterator2 result,
BinaryOperation binary_op);
```

Requires:

For the overloads with no ExecutionPolicy, InputIterator's value type shall be MoveAssignable (Table 25) and shall be constructible from the type of *first. acc (defined below) shall be writable ([iterator.requirements.general]) to the result output iterator. The result of the expression val - acc or binary_op(val, acc) shall be writable to the result output iterator.

For the overloads with an ExecutionPolicy, the value type of ForwardIterator1 shall be CopyConstructible (Table 24), constructible from the expression *first - *first or binary_op(*first, *first), and assignable to the value type of ForwardIterator2.

For all overloads, in the ranges [first, last] and [result, result + (last - first)], binary_op shall neither modify elements nor invalidate iterators or subranges.285

Effects: For the overloads with no ExecutionPolicy and a non-empty range, the function creates an accumulator acc whose type is InputIterator's value type, initializes it with *first, and assigns the result to *result. For every iterator i in [first + 1, last) in order, creates an object val whose type is InputIterator's value type, initializes it with *i, computes val - acc or binary_op(val, acc), assigns the result to *(result + (i - first)), and move assigns from val to acc.

For the overloads with an ExecutionPolicy and a non-empty range, first the function creates an object whose type is ForwardIterator1's value type, initializes it with *first, and assigns the result to *result. Then for every d in [1, last - first - 1], creates an object val whose type is ForwardIterator1's value type, initializes it with *(first + d) - *(first + d - 1) or binary_op(*(first + d), *(first + d - 1)), and assigns the result to *(result + d).

Remarks: For the overloads with no ExecutionPolicy, result may be equal to first. For the overloads with an ExecutionPolicy, the ranges [first, last) and [result, result + (last - first)) shall not overlap.

The use of fully closed ranges is intentional.