Fastest and most readable way to check three booleans

Question

Similar to what is the fastest algorithm for permutations of three condition? and Fastest way to find correct combination with set of 8 booleans

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I have three boolean values (called a, b, and c), each of which has a different action based on which ones are true. There is one little odd situation here; if a is false then c must also be false. There are six possibilities, and this results in a rather long and ugly looking if statement chain. Here's what I came up with:

if (a)
    {
        if (b)
        {
            if (c)
            {
                doAction1(); // a = true, b = true, c = true
            }
            else
            {
                doAction2(); // a = true, b = true, c = false
            }
        }
        else
        {
            if (c)
            {
                doAction3(); // a = true, b = false, c = true
            }
            else
            {
                doAction4(); // a = true, b = false, c = false
            }
        }
    }
    else
    {
        if (b)
        {
            doAction5(); // a = false, b = true, c = false
        }
        else
        {
            doAction6(); // a = true, b = false, c = false
        }
    }

I would prefer if the code was readable and fast, meaning that I would prefer not to use any weird bitwise operations. This isn't a homework assignment, just a simplified version of part of a personal project.

Answer 1

You can always write

if (a && b && c)
{
    action1 ();
}
else if (a && b && ! c)
{
    action2 ();
}
else if (a && ! b && c)
{
    action3 ();
}
else if (a && ! b && ! c)
...

Arguably having fewer nesting levels and fewer braces that are just noise makes it more readable. And you don't need the comments anymore.

Answer 2

if(a && b && c){
    //a b c true
}
else if(!a && b && !c){
    //a false b true c false
}
else if(a && !b && c{
    //a true b false c true
}
//etc