chaining bools in C#

Question

int a, b, c, d, e;
a = b = c = d = e = 1;

if ((a==b) && (b==c) && (c==d) && (d==e))
{
    Console.WriteLine("that syntax is horrible");
}

is there a more elegant way to test multiple equality as above?

maybe an AreEqual(params obj[]) or something? I had a google but didn't find anything.

Answer 1

No, that's the most reasonable way (i mean the most readable, which is the most important).

The real question is, why do you need to do that? It seems like a bad design in the first place ...

Answer 2

A possible implementation of AreEqual(params object[] objects):

(Following Jon Skeet's advice, here's a generic version)

bool AreEqual<T>(params T[] objects)
{
    if (objects.Length <= 1) return true;
    return objects.Skip(1).All(x => x.Equals(objects[0]));
}

The Skip(1) is not strictly necessary either.

Answer 3

Here's a generic version which will avoid boxing (and be more type-safe at compile time):

public static bool AllEqual<T>(T firstItem, params T[] items)
{
    // Omitted error checking
    EqualityComparer<T> comparer = EqualityComparer<T>.Default;
    foreach (T item in items)
    {
        if (!comparer.Equals(firstItem, item))
        {
            return false;
        }
    }
    return true;
}

Note that this won't be as convenient if you really want to pass a bunch of values you've already got in an array, but avoids problems with empty arrays - and means you don't have any redundant comparisons.

Answer 4

If you're comparing simple types and you only have a few use cases then you could create a few utility methods such as:

    bool AllEqual(int first, params int[] numbers)
    {
        return numbers.All(x => x == first);
    }