47 lines
901 B
C#
47 lines
901 B
C#
using System;
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using System.Collections.Generic;
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static class Enumerable
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{
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public static int Sum<TSource> (this IEnumerable<TSource> source, Func<TSource, int> selector)
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{
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return Sum<TSource, int> (source, (a, b) => a + selector (b));
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}
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static TR Sum<TA, TR> (this IEnumerable<TA> source, Func<TR, TA, TR> selector)
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{
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if (source == null)
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throw new ArgumentNullException ("source");
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if (selector == null)
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throw new ArgumentNullException ("selector");
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TR total = default (TR);
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int counter = 0;
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foreach (var element in source) {
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total = selector (total, element);
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++counter;
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}
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if (counter == 0)
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throw new InvalidOperationException ();
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return total;
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}
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}
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class Repro
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{
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public static int Main ()
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{
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var sum = new [] { "1", "2", "3", "4", "5", "6", "7" }.Sum ((s) => int.Parse (s));
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if (sum != 28)
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return 4;
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Console.WriteLine (sum);
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return 0;
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}
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}
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