finding closest value in an array

Question

int[] array = new int[5]{5,7,8,15,20};

int TargetNumber = 13;

For a target number, I want to find the closest number in an array. For example, whe

Answer 1

If you're using .Net 3.5 or above LINQ can help you here:

var closest = array.OrderBy(v => Math.Abs((long)v - targetNumber)).First();

Alternatively, you could write your own extension method:

public static int ClosestTo(this IEnumerable collection, int target)
{
    // NB Method will return int.MaxValue for a sequence containing no elements.
    // Apply any defensive coding here as necessary.
    var closest = int.MaxValue;
    var minDifference = int.MaxValue;
    foreach (var element in collection)
    {
        var difference = Math.Abs((long)element - target);
        if (minDifference > difference)
        {
            minDifference = (int)difference;
            closest = element;
        }
    }

    return closest;
}

Useable like so:

var closest = array.ClosestTo(targetNumber);