Sorting and Searching:Advanced Use of Hashes : Compare « Collections Data Structure « C# / C Sharp
Sorting and Searching:Advanced Use of Hashes
using System;
using System.Collections;
public class AdvancedUseofHashes
{
public static void Main()
{
Employee herb = new Employee("H", 5);
Employee george = new Employee("G", 1);
Employee frank = new Employee("F", 2);
Hashtable employees =
new Hashtable(Employee.HashByName, Employee.SortByName);
employees.Add(herb, "AA");
employees.Add(george, "BB");
employees.Add(frank, "CC");
Employee herbClone = new Employee("H", 000);
string address =(string) employees[herbClone];
Console.WriteLine("{0} lives at {1}", herbClone, address);
}
}
public class Employee: IComparable
{
public Employee(string name, int id)
{
this.name = name;
this.id = id;
}
int IComparable.CompareTo(object obj)
{
Employee emp2 = (Employee) obj;
if (this.id > emp2.id)
return(1);
if (this.id < emp2.id)
return(-1);
else
return(0);
}
public override int GetHashCode()
{
return(id);
}
public static IComparer SortByName
{
get
{
return((IComparer) new SortByNameClass());
}
}
public static IComparer SortById
{
get
{
return((IComparer) new SortByIdClass());
}
}
public static IHashCodeProvider HashByName
{
get
{
return((IHashCodeProvider) new HashByNameClass());
}
}
public override string ToString()
{
return(name + ":" + id);
}
class SortByNameClass: IComparer
{
public int Compare(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;
return(String.Compare(emp1.name, emp2.name));
}
}
class SortByIdClass: IComparer
{
public int Compare(object obj1, object obj2)
{
Employee emp1 = (Employee) obj1;
Employee emp2 = (Employee) obj2;
return(((IComparable) emp1).CompareTo(obj2));
}
}
class HashByNameClass: IHashCodeProvider
{
public int GetHashCode(object obj)
{
Employee emp = (Employee) obj;
return(emp.name.GetHashCode());
}
}
string name;
int id;
}
