Added MultiClassDemo.java file

MulticlassDemo.java

@@ -0,0 +1,46 @@
+class Circle
+{
+
+    double r;
+    double circumference()
+    {
+        return 2*3.14*r;
+    }
+    double area()
+    {
+        return (22/7)*r*r;
+    }
+}
+class Box
+{
+    double width;
+    double height;
+    double depth;
+    double area()
+    {
+        double a;
+        a=(width*height + height*depth + width*depth)*2;
+        return a;
+    }
+    double volume()
+    {
+        double v;
+        v=width*height*depth;
+        return v;
+    }
+
+}
+class MulticlassDemo
+{
+    public static void main(String args[])
+    {
+        Circle c= new Circle();
+        Box b=new Box();
+        c.r=5.0;
+        b.width=3.0;b.height=4.0;b.depth=5.0;
+        System.out.println("Circumference Circle: "+c.circumference());
+        System.out.println("Area circle: "+c.area());
+        System.out.println("Area of Box: "+b.area());
+        System.out.println("Volume of Box: "+b.volume());
+    }
+}