Sort arraylist using custom IComparer : ArrayList « Data Structure « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Data Structure
3. ArrayList

using System;
using System.Collections;

  class Class1
  {
    [STAThread]
    static void Main(string[] args)
    {
            string input;
            ArrayList alPeople = new ArrayList();
            input = Console.ReadLine();

            alPeople.Add( new Person( "a", "b" ));
            alPeople.Add( new Person( "x", "x" ));
            alPeople.Add( new Person( "y", "y" ));
            alPeople.Add( new Person( "z", "z" ));
            
            Console.WriteLine( "\nArray before sort" );
            foreach( Person p in alPeople )
            {
                Console.WriteLine( "   {0} {1}", p.firstName, p.lastName );
            }
            // sort arraylist using custom IComparer
            alPeople.Sort( new Person() );

            // output sorted array
            Console.WriteLine( "\nArray after sort" );
            foreach( Person p in alPeople )
            {
                Console.WriteLine( "   {0} {1}", p.firstName, p.lastName );
            }
    }
  }

    struct Person : IComparer
    {
        public string firstName;
        public string lastName;

        public Person( string first, string last )
        {
            firstName = first;
            lastName = last;
        }

        public int Compare( object a, object b )
        {
            int lNameCmp;
            int fNameCmp;

            Person pa = (Person) a;
            Person pb = (Person) b;

            lNameCmp = String.Compare( pa.lastName, pb.lastName );
            if( lNameCmp != 0 ) return lNameCmp;

            fNameCmp = String.Compare( pa.firstName, pb.firstName );

            return fNameCmp;
        }
    }