Mega Code Archive
Use an interface constraint
<![CDATA[
using System;
class NotFoundException : ApplicationException { }
public interface IUserID {
string Number {
get;
set;
}
string Name {
get;
set;
}
}
class Engineer : IUserID {
string name;
string number;
public Engineer(string n, string num) {
name = n;
number = num;
}
// Implement IUserID
public string Number {
get { return number; }
set { number = value; }
}
public string Name {
get { return name; }
set { name = value; }
}
}
class Manager : IUserID {
string name;
string number;
public Manager(string n, string num) {
name = n;
number = num;
}
// Implement IUserID
public string Number {
get { return number; }
set { number = value; }
}
public string Name {
get { return name; }
set { name = value; }
}
}
class Guest {
}
class IDList<T> where T : IUserID {
T[] idList;
int end;
public IDList() {
idList = new T[10];
end = 0;
}
public bool add(T newEntry) {
if(end == 10)
return false;
idList[end] = newEntry;
end++;
return true;
}
public T findByName(string name) {
for(int i=0; i<end; i++) {
if(idList[i].Name == name)
return idList[i];
}
throw new NotFoundException();
}
public T findByNumber(string number) {
for(int i=0; i<end; i++) {
if(idList[i].Number == number)
return idList[i];
}
throw new NotFoundException();
}
}
class MainClass {
public static void Main() {
IDList<Engineer> plist = new IDList<Engineer>();
plist.add(new Engineer("T", "1"));
plist.add(new Engineer("G", "6"));
plist.add(new Engineer("M", "9"));
try {
Engineer frnd = plist.findByName("G");
Console.Write(frnd.Name + ": " + frnd.Number);
} catch(NotFoundException) {
Console.WriteLine("Not Found");
}
Console.WriteLine();
IDList<Manager> plist2 = new IDList<Manager>();
plist2.add(new Manager("H", "8"));
plist2.add(new Manager("C", "2"));
plist2.add(new Manager("N", "4"));
try {
Manager sp = plist2.findByNumber("4");
Console.WriteLine(sp.Name + ": " + sp.Number);
} catch(NotFoundException) {
Console.WriteLine("Not Found");
}
// The following declaration is invalid
// because Guest does NOT implement IUserID.
// IDList<Guest> plist3 = new IDList<Guest>(); // Error!
}
}
G: 6
N: 4
]]>