Implements IComparable

using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

class Person : IComparable {
public string Name;
public int Age;

public Person(string name, int age) {
Name = name;
Age = age;
}

public int CompareTo(object obj) {
if (obj is Person) {
Person otherPerson = obj as Person;
return this.Age – otherPerson.Age;
} else {
throw new ArgumentException(
“Object to compare to is not a Person object.”);
}
}
}

class Program {
static void Main(string[] args) {
ArrayList list = new ArrayList();
list.Add(new Person(“A”, 30));
list.Add(new Person(“B”, 25));
list.Add(new Person(“B”, 27));
list.Add(new Person(“E”, 22));

for (int i = 0; i < list.Count; i++) { Console.WriteLine("{0} ({1})", (list[i] as Person).Name, (list[i] as Person).Age); } list.Sort(); for (int i = 0; i < list.Count; i++) { Console.WriteLine("{0} ({1})", (list[i] as Person).Name, (list[i] as Person).Age); } } } [/csharp]