Using one else with multiple if statements in C#

Question

Is there a way to quickly check the following logic in C#?

if (a)
{

}
if (b)
{

}
if (c)
{

}
else //none of the above, execute if all above conditions are false
{
  /* do something only if !a && !b && !c  */
}

This differs from using if-else in that a, b, and c can all be true at once, so I can't stack them that way.

I want to run the else block when a, b, and c are all false without writing if (!a && !b && !c). This is because the code can get quite messy when the if conditions become more complex. It requires rewriting a lot of code.

Is this possible?

Answer 1

Firstly, no, else blocks only respect the if clause immediately above them, so you'll need an alternative.

This option isn't especially "clean", but I'd do:

bool noneAreTrue = true;
if(a)
{
    noneAreTrue = false;
}
if(b)
{
    noneAreTrue = false;
}
if(c)
{
    noneAreTrue = false;
}
if(noneAreTrue)
{
    //execute if all above conditions are false
}

Also, if your conditions are really pretty big, I recommend the rule G28 (Encapsulate Conditionals) from the book Clean Code from Robert C. Martin.

It is pretty verbose, but can be easier to read in some instances:

public void YourMethod()
{
    if(SomeComplexLogic())
    {
    }
    if(SomeMoreLogic())
    {
    }
    if(EvenMoreComplexLogic())
    {
    }
    if(NoComplexLogicApply())
    {
    }
}

private bool SomeComplexLogic(){
    return stuff;
}

private bool EvenMoreComplexLogic(){
    return moreStuff;
}

private bool EvenMoreComplexLogic(){
    return evenMoreStuff;
}

private bool NoComplexLogicApply(){
    return SomeComplexLogic() && EvenMoreComplexLogic() && EvenMoreComplexLogic();
}