LINQ · interview question

What does this program print?

What does this code output?Medium

var numbers = new List<int> { 1, 2, 3 };
var query = numbers.Where(n => n > 1);
numbers.Add(4);
Console.WriteLine(query.Count());

234It throws InvalidOperationException

Answer and explanation

Correct answer

B. 3

Where uses deferred execution: query is just a recipe. It runs when Count() enumerates, after 4 was added, so it counts 2, 3 and 4.

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