Check if several booleans have the same value

Question

I have three boolean variables. I need to check if all three are true or all three are false.

I can do this in a 'dummy' way:

bool areSame = false; 
if(a && b && c)    
    areSame = true; 
else if (!a && !b && !c)
    areSame = true;

I'd like to know if there is another more elegant solution.

Answer 1

You can use the equality operator on booleans too:

bool areSame = (a == b) && (a == c);

Answer 2

Sure, you're only comparing three here, but what about the future? You might have to compare ten booleans to each other somewhere down the road.

    class Program
        {
            static void Main(string[] args)
            {
                Console.WriteLine(false.AllEqual(false, false)); 
                Console.WriteLine(true.AllEqual(false, false));
                Console.WriteLine(true.AllEqual(true, false));

                bool a = true;
                bool b = false;
                bool c = true;
                Console.WriteLine(a.AllEqual(b, c));
                b = true;
                Console.WriteLine(a.AllEqual(b, c));
                Console.ReadLine();
            } 
        }

        static class Extensions
    {
        static public  bool AllEqual(this bool firstValue, params bool[] bools)
        {
            return bools.All(thisBool => thisBool == firstValue);
        }
    }

Answer 3

how about using this?

areSame = (a == b && b == c);

Answer 4

What about:

bool areSame = (a && b && c) || (!a && !b && !c) ? true : false;

Answer 5

What about this approach? It will allow you to pass in as many bools and see if the min number of trues are met.

public static bool AreMinNumberOfTruesMet(int minNumOftrue, params bool[] bools)
{
    var totalTrue = bools.Count(boolean => boolean == true);

    return totalTrue >= minNumOftrue;
}

Answer 6

Or in one line :

bool allSame = !bools.Any(b => b != bools[0])

Answer 7

//all same
bool allSame = a == b == c == d;

//all false
bool allFalse = a == b == c == d == false;