Mega Code Archive
0175 Generic type
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Classes and structs can be defined with one or more type parameters.
Client code supplies the type when it creates an instance of the type.
For example, the List<T> class in the System.Collections.Generic namespace is defined with one type parameter.
Client code creates an instance of a List<string> or List<int> to specify the type that the list will hold.
Generic type is a type with type parameter.
The type parameter is only a place holder.
The following code defineds a generic Stack:
using System;
public class Stack<T>
{
private int position;
T[] data = new T[100];
public void Push(T obj) {
data[position++] = obj;
}
public T Pop() {
return data[--position];
}
}
class Test
{
static void Main()
{
Stack<int> stack = new Stack<int>();
stack.Push(5);
stack.Push(10);
int x = stack.Pop();
int y = stack.Pop();
}
}
A bag is a data structure that can contain zero or more items, including duplicates of items.
using System;
using System.Collections.Generic;
public class Bag<T>
{
private List<T> items = new List<T>();
public void Add(T item)
{
items.Add(item);
}
public T Remove()
{
T item = default(T);
if (items.Count != 0)
{
item = items[0];
items.RemoveAt(0);
}
return item;
}
// A method to provide an enumerator from the underlying list
public IEnumerator<T> GetEnumerator()
{
return items.GetEnumerator();
}
// A method to remove all items from the bag and return them
// as an array
public T[] RemoveAll()
{
T[] i = items.ToArray();
items.Clear();
return i;
}
}
public class MainClass
{
public static void Main(string[] args)
{
// Create a new bag of strings.
Bag<string> bag = new Bag<string>();
bag.Add("D");
bag.Add("B");
bag.Add("G");
bag.Add("M");
bag.Add("N");
bag.Add("I");
foreach (string elem in bag)
{
Console.WriteLine("Element: {0}", elem);
}
// Take four strings from the bag and display.
Console.WriteLine("Removing individual elements");
Console.WriteLine("Removing = {0}", bag.Remove());
Console.WriteLine("Removing = {0}", bag.Remove());
Console.WriteLine("Bag contents are:");
foreach (string elem in bag)
{
Console.WriteLine("Element: {0}", elem);
}
// Remove the remaining items from the bag.
Console.WriteLine("Removing all elements");
string[] s = bag.RemoveAll();
Console.WriteLine("Bag contents are:");
foreach (string elem in bag)
{
Console.WriteLine("Element: {0}", elem);
}
}
}
The output:
Element: D
Element: B
Element: G
Element: M
Element: N
Element: I
Removing individual elements
Removing = D
Removing = B
Bag contents are:
Element: G
Element: M
Element: N
Element: I
Removing all elements
Bag contents are:
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