Elegantly determine if more than one boolean is “true”

Question

I have a set of five boolean values. If more than one of these are true I want to excecute a particular function. What is the most elegant way you can think of that would al

Answer 1

If there were millions instead of just 5 you could avoid Count()and do this instead ...

public static bool MoreThanOne (IEnumerable<bool> booleans)
{
    return booleans.SkipWhile(b => !b).Skip(1).Any(b => b);
}

Answer 2

I would do something like this, using the params argument.

        public void YourFunction()
        {
            if(AtLeast2AreTrue(b1, b2, b3, b4, b5))
            {
                // do stuff
            }
        }

        private bool AtLeast2AreTrue(params bool[] values)
        {
            int trueCount = 0;
            for(int index = 0; index < values.Length || trueCount >= 2; index++)
            {
                if(values[index])
                    trueCount++;
            }

            return trueCount > 2;

        }

Answer 3

I have a much much better one now and very short!

bool[] bools = { b1, b2, b3, b4, b5 };
if (bools.Where(x => x).Count() > 1)
{
   //do stuff
}

Answer 4

I was going to write the Linq version, but five or so people beat me to it. But I really like the params approach to avoid having to manually new up an array. So I think the best hybrid is, based on rp's answer with the body replace with the obvious Linqness:

public static int Truth(params bool[] booleans)
{
    return booleans.Count(b => b);
}

Beautifully clear to read, and to use:

if (Truth(m, n, o, p, q) > 2)

Answer 5

if (NumberOfTrue(new List<bool> { bool1, bool2, bool3, bool4 }) >= 2)
{
    // do stuff
}

int NumberOfTrue(IEnumerable<bool> bools)
{
    return bools.Count(b => b);
}

Answer 6

Not exactly pretty... but here's another way to do it:

if (
    (a && (b || c || d || e)) ||
    (b && (c || d || e)) ||
    (c && (d || e)) ||
    (d && e)
)