实例变量

import java.io.*;
class Marks
{   
    //These variables are instance variables.
    //These variables are in a class and are not inside any function
    int engMarks;
    int mathsMarks;
    int phyMarks;
}
 
class MarksDemo
{
    public static void main(String args[])
    {   //first object
        Marks obj1 = new Marks();
        obj1.engMarks = 50;
        obj1.mathsMarks = 80;
        obj1.phyMarks = 90;
 
        //second object
        Marks obj2 = new Marks();
        obj2.engMarks = 80;
        obj2.mathsMarks = 60;
        obj2.phyMarks = 85;
 
        //displaying marks for first object
        System.out.println("Marks for first object:");
        System.out.println(obj1.engMarks);
        System.out.println(obj1.mathsMarks);
        System.out.println(obj1.phyMarks);
     
        //displaying marks for second object
        System.out.println("Marks for second object:");
        System.out.println(obj2.engMarks);
        System.out.println(obj2.mathsMarks);
        System.out.println(obj2.phyMarks);
    }
}