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| template<typename I , typename S , typename T , typename Op  = plus, typename P  = identity> requires sentinel_for<S, I> && input_iterator<I> && indirectly_binary_invocable_<Op, T *, projected<I, P>> && assignable_from<T &, indirect_result_t<Op &, T *, projected<I, P>>>
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| T | operator() (I first, S last, T init, Op op=Op{}, P proj=P{}) const | 
|  | 
| template<typename Rng , typename T , typename Op  = plus, typename P  = identity> requires input_range<Rng> && indirectly_binary_invocable_<Op, T *, projected<iterator_t<Rng>, P>> && assignable_from< T &, indirect_result_t<Op &, T *, projected<iterator_t<Rng>, P>>>
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| T | operator() (Rng &&rng, T init, Op op=Op{}, P proj=P{}) const | 
|  |