JAVA Program to calculate percentage marks of the student

/*
2. Write a program that calculate percentage marks of the student if marks of 6 subjects are given.
*/

import java.util.Scanner;

class Percent_pract2_2{
public static void main(String args[]){
Scanner sc = new Scanner(System.in);
int sum = 0;
float avg;
int marks[] = new int[5];
System.out.println("Enter Marks of subject 1");
marks[0]=sc.nextInt();
System.out.println("Enter Marks of subject 2");
marks[1]=sc.nextInt();
System.out.println("Enter Marks of subject 3");
marks[2]=sc.nextInt();
System.out.println("Enter Marks of subject 4");
marks[3]=sc.nextInt();
System.out.println("Enter Marks of subject 5");
marks[4]=sc.nextInt();


for(int i=0;i<marks.length;i++){
sum += marks[i];
}
avg = (float)sum/marks.length;
System.out.println("Sum = "+sum);
System.out.println("percentage = "+avg);
}

}

JAVA program to convert rupees to dollar

/*
1. Write a JAVA program to convert rupees to dollar. 60 rupees=1 dollar
*/

class Convert_pract1_1
{
public static void main(String args[])
       {
int rs =Integer.parseInt(args[0]);
float dlr;
dlr= (float)rs/60;
System.out.println("Rs = "+rs);
System.out.println("Dollar = "+dlr);
}
}

File Handling using Object Input Output Stream

import java.io.*;
import java.util.*;
class ObjectReadWrite implements Serializable, Comparable <ObjectReadWrite>
{
int no;
String name;
ObjectReadWrite(int i,String s)
{
this.no=i;
this.name=s;
}
public String toString()
{
return "TP Data : "+this.no+":"+this.name;
}
public int compareTo(ObjectReadWrite a1)
{
return this.name.compareTo(a1.name);
}
public static void main(String args[]) throws Exception
{
TreeSet<ObjectReadWrite> aw = new TreeSet<ObjectReadWrite>();
aw.add(new ObjectReadWrite(1,"ABC"));
aw.add(new ObjectReadWrite(2,"DDF"));
aw.add(new ObjectReadWrite(3,"DAF"));
aw.add(new ObjectReadWrite(4,"DCF"));

//Writing Objects From TreeSet
ObjectOutputStream os=new ObjectOutputStream(
new FileOutputStream(
new File("Test.dat")));
os.writeObject(aw);
os.close();



//Reading Objects into TreeSet
TreeSet ar = new TreeSet();
ObjectInputStream is=new ObjectInputStream(
new FileInputStream(
new File("Test.dat")));

ar=(TreeSet)is.readObject();
is.close();


Iterator ir = ar.iterator();
while(ir.hasNext())
{
System.out.println((ObjectReadWrite)ir.next());
}

}
}