C#•3mo ago

✅ Strange output of my code

        var query = Enumerable.Range(1, 1000)
            .Where(x => x % 2 == 0)
            .Aggregate((x, y) => x * y);

        Console.WriteLine(query);

        var query = Enumerable.Range(1, 1000)
            .Where(x => x % 2 == 0)
            .Aggregate((x, y) => x * y);

        Console.WriteLine(query);

why does this output 0? is it due to overflow, and if it is, why is an exception not thrown?

3 Replies

PixxelKick•3mo ago

By default overflow/underflow doesn't throw but you can enable it via a setting in your csproj: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/compiler-options/language#checkforoverflowunderflow Or by wrapping it in checked(...) IE in your case: .Aggregate((x, y) => checked(x * y))

C# Compiler Options - language feature rules - C#

C# Compiler Options for language feature rules. These options control how the compiler interprets certain language constructs.

PixxelKick•3mo ago

Since your math there is effectively doing 2^125250 I think, if I did the math right. 2x4x6x8x10....1000 Is the same as 2^(1+2+3+4+5...500) Which can then just be 2^(1+500+2+499+3+498...) Which becomes 2^(501+501+501...) = 2^(501*250) = 2^125250 = 37,704 digits long numbah

2spooky2play•3mo ago

cool, thank you!

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✅ Strange output of my code