using System;

    public class Example
    {
       public static void Main()
       {
          Random rnd = new Random();
          int min_value = 10;
          int max_value = 20;

          Console.WriteLine("n20 random integers from 10 to 20:");
          for (int ctr = 1; ctr <= 20; ctr++)
          {
             Console.Write("{0,6}", rnd.Next(min_value, max_value));
             if (ctr % 5 == 0) Console.WriteLine();
          }
       }
    }

var r=new Random();
r.Next(int.MinValue,int.MaxValue)