class Program
 {
     static void Main(string[] args)
     { 
         String []chars = {"z", "x", "y", "z", "y"};
         for (int i = 0; i < chars.Length; ++i)
         for (int j = i + 1; j < chars.Length; ++j)
         if(chars[i].CompareTo(chars[j]) == 0)
         Console.WriteLine(chars[j]);
         Console.ReadLine();
     }
 }

String a = "Csharp";
String b = "CSHARP";
int c;
c = a.CompareTo(b);
Console.WriteLine(c);

static void Main(string[] args)
 {
     String a = "Ilove";
     String b = "CSHARP";
     b = string.Concat(a, '  ', b);
     Console.WriteLine(b);
     Console.ReadLine();
 }

static void Main(string[] args)
  {
      String a = "Ilove";
      String b = "CSHARP";
      b = string.Concat(a,' ',b);
      string d = b.TrimStart('I', 'l', 'o', 'H');
      Console.WriteLine(d);
      Console.ReadLine();
  }

static void Main(string[] args)
 {
     String c = "  Hello Computer ";
     String a = c.Trim();
     Console.WriteLine("\"" + s + "\"");
 }

static void Main(string[] args)
 {
     String c = "Hello";
     String a = c + "Bye";
     Console.WriteLine(a);
     Console.ReadLine();
 }

static void Main(string[] args)
{
    String c = "Hello";
    String a ;
    a = c.Replace('l', 'w');
    Console.WriteLine(a);
    Console.ReadLine();
}