cw2c.java

samll awt programs for the beginner.

/**
* Author: Jing Han
* Date; 12/11/03
*Module: G6DICp
* Title: ICP Coursework 2
* SCSiT Username: jxh23m
*/




import java.io.*;
import java.awt.*;
import java.util.*;


class MainWindow extends Frame
{
    //declare class variable
    String title;
    
    /*------------------------------------------------------------------------
    *mainwindow method to set up layout,size and backgroud of screen
    *constructor doStuff method
    *--------------------------------------------------------------------------*/
    public MainWindow()
    {
     setLayout(null);
     setSize(400,400);
     setBackground(Color.gray);
     setTitle("Pie Chart");
     doStuff();
     
     } //end of mainwindow   

    
    /*------------------------------------------------------------------------------------
    *doStuff method: read data from file, calculate the angle and store angle into vector
    *print out angle and data in the file
    *------------------------------------------------------------------------------------*/
    public void doStuff()
    {
         //prompt for filename
        System.out.print("Enter data file:"+"  ");
        String filename=TButils.readln();
        
        //declare varialbe title and instantiate vector
        title = "";
        Vector data=new Vector();
        double sum=0;
        Double myDouble;
        double datavalue; 
        
        
        //instantiate RandomAeccessFile. myData file is opened for reading
        try 
        {
            RandomAccessFile inFile=new RandomAccessFile(filename,"r");
            String line; 
            int lineNo=0;
            
            while((line=inFile.readLine())!=null) 
            {
               
                if( lineNo == 0 )
                {
                    title=line;
                 }
                 
                 else
                 {
                 	//trim leading spaces from line
					String newline=line.trim();          
                    myDouble=Double.valueOf(line);    
                    datavalue=myDouble.doubleValue();    
                    sum=sum+datavalue;        
                    data.addElement(myDouble); 
                 }
          
            
                lineNo++; 
       
            }
         }
         catch (IOException e)
         {
            System.out.println("An i/o error has occured ["+e+"]");
         }// end of catch exception

      
         //print out title and line of words
         System.out.println("Title:"+"  "+title);
     	 System.out.println("     "+"Data"+"     "+"Angle(degree)");

       /*--------------------------------------------------------------------------------
        *  instatiate new vector angle and delacare new variables
        * get number out of the vector data 
        * convert int number to double for calculation angle
        * cast the result double angle to Double and put into vector angle
        ---------------------------------------------------------------------------------*/
        Double tmpValue;     		  
        double value;           		  
        double angleDouble;      		 
		int angleInt;
		Double myD;
		Vector angle=new Vector();	 
		 //calculate the angle and wrap into the vector
         for(int n=0;n<data.size();n++)
         {
         
              tmpValue=(Double)data.elementAt(n);	
              value=tmpValue.doubleValue();		
              angleDouble=Math.round(360*value/sum);	
		      myD=new Double(angleDouble);
		      angleInt=myD.intValue();
              angle.addElement(new Integer(angleInt));
         
         }
     
     //print out data in two vectors
      for(int n=0;n<angle.size();n++)
     {
        System.out.println("      "+((Double)data.elementAt(n)).intValue()+"       "+angle.elementAt(n));
     }//end of for loop 
     	   	
    }//end of doStuff

   /*-----------------------------------------------------------------------
     *override the paint method and name as super.paint
     *-----------------------------------------------------------------------*/ 
    public void paint(Graphics g)
    {
        super.paint(g);
        
       
        // draw a yellow circle
        g.setColor(Color.yellow);    
        g.drawOval(100,60,100,100); // NB draw two concentric circles (to make it thick)
        g.drawOval(101,61,98,98);
            
        // write the message in white SansSerif bold 16
        g.setColor(Color.blue);            
        g.setFont(new Font("SansSerif", Font.BOLD, 16));
        g.drawString(title,105,45);
    }
}//end of mainwindow class


/*---------------------------------------------------------------------------------
  *main program
  *call Mainwindow class
  *instantiate the mainwindow class 
*-----------------------------------------------------------------------------------*/
class cw2c
{
    public static void main(String args[])
    {
     MainWindow myWindow=new MainWindow();
     myWindow.show();
    }
}//end of main class