when would you use this? C#

Question

I just started learning C# yesterday and I left off at the console playground. it teaches you that when typing:

static void Main(string[] args)
{
int x = 10;
double y = 20;

Console.WriteLine("x = {0}; y = {1}", x, y);
}
// Output: x = 10; y = 20

you will output x = 10; y = 20.
I have played with this a bit and got:

Console.WriteLine("{0} {1}", x, y);

and it types out 10 20. when would you use this?

Answer 1

String formating is a succinct syntax, to shorten the old syntax such as

"The variable is " + variable.