What are some examples of deferred execution in programming?

What are some examples of deferred execution in programming?

Deferred execution is a programming concept where the evaluation of an expression is delayed until its value is actually needed. A common example is in LINQ queries in C#, where the query is not executed until you iterate over the results.

Can you give me a specific code example?

Sure! Here's a simple example in C#:

var numbers = new List<int> { 1, 2, 3, 4, 5 };
var query = numbers.Where(n => n > 2);

// The query is not executed yet.
foreach (var number in query) {
    Console.WriteLine(number);
}

In this case, the Where method creates a deferred execution query.

What are the benefits of using deferred execution?

Deferred execution can improve performance by avoiding unnecessary computations and can also allow for more flexible query composition.

Are there any downsides to using it?

Yes, one downside is that it can lead to unexpected behavior if the data source changes before the execution occurs, potentially resulting in stale data.