一个java的猜数字游戏 适合初学者

				//file GuessNumber.java
				//第三章,程序流程.
				//通过日期：2003,11,3
				//功能：猜四位数，7次机会。
				//规模：89
				import javax.swing.JOptionPane;//JOptionPane
				
				public class GuessNumber
				{
					public static void main(String[] args)
					{
						int a=0;//right number and right position
						int b=0;//wrong number and right position
						int count;//number of guess
						int[] original = new int[4];//right number
						int[] guess = new int[4];//number you have guessed
						String input;
				        try{
						do{
							//product a new number
							for(int i=0;i							{
								original[i] = (int)(Math.random()*10);
								for(int j = 0;j								{
									if((i!=j)&&(original[i]==original[j]))
									   {
									   		i=i-1;
									   		break;
									   }
								}
							}
						   for(count=0;count						   {
						   		input = JOptionPane.showInputDialog
						   				("Please input your number(integer)");
						   		int number = Integer.parseInt(input);
						   		guess[0] = number/1000;
						   		guess[1] = number/100 - 10 * guess[0];
						   		guess[2] = number/10 - 100 * guess[0] - 10*guess[1];
						   		guess[3] = number%10;
				
						   		for(int i = 0;i						   		{
									for(int j = 0;j									{
										if(guess[i]==original[j])
										{
											if(i==j)a++;
											else b++;
										}
									}
								}
							    if(a==4)
							        {
								     JOptionPane.showMessageDialog(null,"You are so clever!",
								         "You win.",JOptionPane.INFORMATION_MESSAGE);
						            }
						        else
						            {
										for(int i = 0;i										{
											System.out.print(guess[i]);
										}
											System.out.println("  "+a+"A"+b+"B");
									}
						        a=0;
						        b=0;
				
						   }
						   JOptionPane.showMessageDialog(null,"You lose!",
						               "Right number is" + original[0] + original[1]
						                    + original[2] + original[3],
						                  JOptionPane.INFORMATION_MESSAGE);
				
						   input=JOptionPane.showInputDialog
						               ("Do you want to try again?(Y/N)");
						   input=input.toUpperCase();
				
						}while(input.equals("Y"));
					}
					  catch(Exception e)
					  {
						System.out.println("Something is wrong!");
						System.exit(0);
					  }
				
					}
				}