private static TAccumulate Aggregate <TSource, TAccumulate>(
this IEnumerator <TSource> iterator,
TAccumulate accumulation,
Func <TAccumulate, TSource, int, TAccumulate> func,
int index) => iterator.MoveNext()
? iterator.Aggregate(func(accumulation, iterator.Current, index), func, checked (index + 1))
: accumulation;
public static TAccumulate Aggregate <TSource, TAccumulate>(
this IEnumerable <TSource> source,
TAccumulate seed,
Func <TAccumulate, TSource, int, TAccumulate> func)
{
using (IEnumerator <TSource> iterator = source.GetEnumerator())
{
return(iterator.Aggregate(seed, func, 0));
}
}
public static TSource Aggregate <TSource>(
this IEnumerable <TSource> source,
Func <TSource, TSource, TSource> func)
{
using (IEnumerator <TSource> iterator = source.GetEnumerator())
{
if (!iterator.MoveNext())
{
throw new InvalidOperationException("Sequence contains no elements.");
}
return(iterator.Aggregate(
iterator.Current, (accumulate, value, index) => func(accumulate, value), 1));
}
}
