What does "Result: {0}" mean in the code?

Question

do {
Console.Write("x = ");
int x = Convert.ToInt32(Console.ReadLine());

Console.Write("y = ");
int y = Convert.ToInt32(Console.ReadLine());

int sum = x+y;
Console.WriteLine("Result: {0}", sum);
}
while(true);

Answer 1

{0} acts like a placeholder and will be replaced by the given value which in your code is sum
if no value provided it will act like a normal string

Answer 2

Thanks