What is the Double.PositiveInfinity field in C#?

// use System
using System;
// create class
class DoublePositiveInfinity
{   
    // main method
    static void Main()
    {
      // print field value
      Console.WriteLine(Double.PositiveInfinity);
      // check if positive infinity
      if(-23/0.0 == Double.PositiveInfinity){
        Console.WriteLine("Positive Infinity");
      }else{
        Console.WriteLine("Not Positive Infinity");
      }
      // check if positive infinity
      if(23/0.0 == Double.PositiveInfinity){
       Console.WriteLine("Positive Infinity");
      }else{
        Console.WriteLine("Not Positive Infinity");
      }
    }
}