Am I understanding placeholders right? Why do I still need "yourName"?

Question

So, hi. I'm Oliver, and I just got this app after some people recommended me it. I'm a total newbie to code, if you couldn't guess.

So, for the past 30 minutes, I've been struggling to understand placeholders. I'm 99% certain I understand variables, but placeholders are at a complete lost to me.

So, this is the way I rationalized the concept:
Values to be used in the string are somewhat like a numbered list starting at 0. Like,

#0: int = 89
#1: double = 27

And so on. And, that seemed to work. But, I got to a string of code that broke that reality, and now I'm back to square one and don't get it. In the code {0} and yourName are needed in the Console.WriteLine line in order to run it!

So, is my analogy to lists correct? Or am I confused? Sorry for being a total noob at code, but your help would be great!

(Here's the code)
string yourName;
Console.WriteLine("What is your name?");
yourName = Console.ReadLine();

Console.WriteLine("Hello {0}", yourName);

Answer 1

Yes you are.

{0} is pointing at the first element behind the "," which is yourName

It does not matter whether the variable is a string, integer, or double.

In this example {0} are both need, but the are several ways to do it.

Console.WriteLine("Hello" + yourName);
is also valid.

Answer 2

you could also write
Console.WriteLine($”Hello” {yourName});