How do I return nothing in function with return type double.

Question

I use a function with return type double and i want to return nothing (not zero).
EDIT:My code looks like this and in case of error i want the console to output the error message only(but it wont allow me as it requires value to return)

public double pop()
{
if (--position<0)
{
Console.WriteLine("There are no elements in Stack");
//here I should insert sth
}
else
return Sztos[position];
}

Answer 1

make that return type of that function be void then...

Answer 2

If c# supports exceptions, generate one and correctly handle it at a point it makes the most sense in the call chain.

Answer 3

What we did before exceptions existed, was return a boolean plus double in a structure. If the boolean was true, the double was valid. Otherwise, the caller did it's error handling. If it couldn't finish it's processing correctly, it passed it to it's caller. This got very complex, which is one reasons exceptions were invented.

Answer 4

Could you post the full code?
one option is that you could have a default value, like -1.0 that, in the main function, would have an if statement to test the return for that value. not the best solution, and it may not work depending on what your code does with the value, but if you don't want to change the return type or catch exceptions (which is the best option), then you could do it

Answer 5

You can't. You have to change the return type. That's what type systems are for.

Answer 6

Since the NaN constant exists, it could be returned when your error occurs and you don't have a valid double. The caller, of course, should test for it.

Answer 7

If you don't want to return a double then don't use the return type double. Use the void return type and you don't even have to specify a return statement.

Answer 8

And nowadays the cool kids do the monads. Which is safe in such a, way that you cannot ignore it, and simple as long as you chain but not stack them.

Answer 9

an double type function can't return null. only numbers type double or zero