TonnyXu

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;

namespace CSharpBasic
{
    class Program
    {

TonnyXu

public static string reverseByAPI(string input){
    if (string.IsNullOrEmpty(input)) return input;

    char[] inputArrary = input.ToCharArray();
    Array.Reverse(inputArrary);

    return new string(inputArrary);
}

TonnyXu

public static string reverseByArray(string input)
{
	if (string.IsNullOrEmpty(input)) return input;

	int halfLength = input.Length >> 1;
	char[] inputArray = input.ToCharArray();
	char temp;
	for (int i = 0; i < halfLength; i++)
	{
		temp = inputArray[i];

TonnyXu

3611 ticks.  ReverseByAPI(Length:1), runs 10000 times.
3581 ticks.  ReverseByXor(Length:1), runs 10000 times.
===============
4955 ticks.  ReverseByAPI(Length:10), runs 10000 times.
5349 ticks.  ReverseByXor(Length:10), runs 10000 times.
===============
9553 ticks.  ReverseByAPI(Length:100), runs 10000 times.
27669 ticks.  ReverseByXor(Length:100), runs 10000 times.
===============
120702 ticks.  ReverseByAPI(Length:1000), runs 10000 times.

TonnyXu

package basic.java;

interface Reverse{
	public String reverse(String s);
}

class ReverseByArray implements Reverse{
	public String reverse(String s){
		if (null == s || s.equals("")) return s;
		

TonnyXu

Original String:1234567890
Reversed String: 0987654321(Reverse by array)
Original String:1234567890
Reversed String: 0987654321(Reverse by array 2)
Original String:1234567890
Reversed String: 0987654321(Reverse by api)
--------
Original String:123
Reversed String: 321(Reverse by array)
Original String:123

TonnyXu

public final class Singleton {

	private static final Singleton INSTANCE = new Singleton();
	
	private Singleton(){
		// Do nothing, make sure user can not create object directly
		if (null != INSTANCE){
			throw new IllegalArgumentException("Already instantiated.");
		}
	}

TonnyXu

public final class Singleton3{
	private static class Handler{
		private static final Singleton3 INSTANCE = new Singleton3();
	}
	
	private Singleton3(){
		if (null != Handler.INSTANCE){
			throw new IllegalArgumentException("Already instantiated.");
		}
	}

TonnyXu

public class Singleton5 {
	private static volatile Singleton5 INSTANCE = null;
	
	private Singleton5(){
		if (null != INSTANCE){
			throw new IllegalArgumentException("Already instantiated.");
		}
	}
	
	public static Singleton5 getInstance(){

TonnyXu

public enum Singleton6{
	INSTANCE;
	
	private Object s = new Object();
	
	// Invoke this like 
	// Singleton6.INSTANCE.doSomething();
	public Object doSomething(){
		return s;
	}