import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.Externalizable;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;

public class PGM implements Externalizable{
	String magicnumber;
	int breite;
	int hoehe ;
	int lichtintens;
	int r; //lichtintensität
	byte matrix[][] ;


public PGM(){}
	
	
public PGM(String magicnumber,int breite,int hoehe,int lichtintens,byte matrix[][])
{
	this.magicnumber = magicnumber;
	this.breite= breite;
	this.hoehe = hoehe;
	this.lichtintens = lichtintens;
	this.matrix = matrix;
}

String writeMatrix()
{
	String str = "";
	for(int a =0;a<this.matrix.length;a++)
	{
		for(int b=0;b<this.matrix[0].length;b++)
		{
			str = str+ this.matrix[a][b];
		}
	}
	return str ;
	
}




public void writeExternal(ObjectOutput out) throws IOException 
		{
		System.out.println("Schreibe in Datei..");
		out.writeChars(magicnumber);
		out.writeInt(breite);
		out.writeChars(" ");
		out.writeInt(hoehe);
		out.writeChars(" ");
		out.writeInt(255);
		out.writeChars(this.writeMatrix());
		}


public void readExternal(ObjectInput in) throws IOException,
		ClassNotFoundException 
		{
		System.out.println("Lese Datei ein.");
	
		}


}

 


class hauptklasse 
{
	
		public static void main(String[] args)
		{
			int r=255;
			int breite= 10;
			int hoehe = 20;
			
			byte matrix[][]=new byte[breite][hoehe];
			
			for(int i =0;i<breite;i++)
			{
				for(int j=0;j<hoehe;j++)
				{
					matrix[i][j]=(byte) (r*(Math.sin((Math.PI*i)/50)*Math.sin((Math.PI*j)/50)));
				}
			
			}
			
				schreiben(matrix);
		 
		}
		

	static void schreiben(byte[][]matrix){
		try
		{
			File f = new File("./dir");
			if(!f.exists() &&!f.mkdirs())
			{
				System.out.println("Kann Verzeichnis nicht anlegen");
				System.exit(1);
			}
			f = new File("./dir/bild.pgm");
			if(!f.exists())
			{
				if(!f.createNewFile() || !f.canWrite())
				{
					System.out.println("Kann Datei nicht beschreiben!");
					System.exit(1);
				}
			
				
				PGM bild = new PGM("P5",10,20,255,matrix);
		
				//System.out.println(v);

				ObjectOutputStream o = new ObjectOutputStream(new FileOutputStream(f));
				o.writeObject(bild);
				o.close();
			}
		}	
		catch(java.io.IOException e) { System.out.println(e);}

		}//schreiben ende
	
	
}//Ende klasse