title: What does "x : {0}" means exactly?
body: <pre><code>using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  
  namespace FloatConversion
  { 
      class MainApp
      {
          static void Main(string[] args)
          {
              float a = 69.6875f;
              Console.WriteLine("a : {0}", a);
  
              double b = (double)a;
              Console.WriteLine("b : {0}", b);
  
              Console.WriteLine("69.6875 == b : {0}", 69.6875 == b);
  
              float x = 0.1f;
              Console.WriteLine("x : {0}", x);
  
              double y = (double)x;
              Console.WriteLine("y : {0}", y);
  
              Console.WriteLine("0.1 == y : {0}", 0.1 == y);
  
  
  
              Console.ReadLine();
          }
      }
  }
  </code></pre>
  
  <p>I just started learning C#. As a Newbie, I was wondering that what <code>a : {0}</code> means in <code>Console.WriteLine()</code> method.</p>
  
  <p>similarly, what does <code>69.6875 == b : {0}</code> mean? how can it be displayed as a boolean?</p>
  
  <p>Thank u in advance.</p>