hello.java

内涵了200个适合Java初学者学习的小程序

import java.lang.*;
import java.io.*;
import java.util.*;
import com.freecn.utils.*;

public class Hello extends Object
{

    /*
    method:       main
    params:
                  1. String[] args
    return type:  void
    create time:  2004-04-01 23:34:09
    author:       gshn
    */
    public  static void main(String[] args)
    {
        //prompt input double array
        Common.printMsg("Please input double array(multi double split with space,i.e 12.1 2.3 3.4)");
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        //read a line from console input stream
        try
        {
            String inputArrayStr = in.readLine();
            //parse the input line string into double array
            StringTokenizer st = new StringTokenizer(inputArrayStr);
            ArrayList al = new ArrayList();
            while (st.hasMoreTokens())
            {
                al.add(st.nextToken());
            }
            double[] inputArray = new double[al.size()];
            //format string to double,if error occurs, exit the application
            for (int i=0;i<inputArray.length;i++)
            {
                try
                {
                    inputArray[i] = Double.parseDouble( al.get(i).toString() );
                }
                catch(Exception e)
                {
                    System.out.println(al.get(i).toString() + " isn't a valid double format,error occurs.");
                    return;
                }
            }
            
            // sort double array
            sort(inputArray);
            // print out the double array after sorted
            for (int i=0;i<inputArray.length;i++)
                System.out.print(inputArray[i]+"\t");

            System.out.println();

        }
        catch(IOException ioe)
        {
            System.out.println(ioe.getMessage());
        }

    }

    /*
    method:       sort
    params:
                  1. double[] list
    return type:  void
    create time:  2004-04-03 23:42:03
    author:       gshn
    */
    public static void sort(double[] list)
    {
        int i,j;
        boolean done=false;
        double temp;
        j=1;
        while( (j<list.length) && (!done) )
        {
            done=true;
            for(i=0;i<list.length-j;i++)
            {
                if(list[i]>list[i+1])
                {
                    done=false;
                    temp=list[i];
                    list[i]=list[i+1];
                    list[i+1]=temp;
                }
            }
            j++;
        }
    }
}