Those years, learn together Java 4-3

/**4-3

* Derive a subclass for the rectangle class defined in Experiment 3: a square class. If the square operation is also to find the circumference and area

* What methods does this subclass need to define in addition to the methods inherited from the parent class?

* Lists all fields and methods of the square class.

* Programming to check, run the written square class

**/

public class firstprogram{public static void main  (String[] args) {Square  square1 = new square (8); Square square2 = new square (25); System.out.println ("the perimeter of square1 is: "  + square1.perimeter ()); System.out.println ("the area of square1 is: "  + square1.area ()); System.out.println ("the perimeter of square2 is: "  + square2.perimeter ()); System.out.println ("the area of square2 is: "  + square2.area ());}} class rectangle{protected int length;protected int width; rectangle  () {}rectangle (int l, int w) {this.length = l;this.width = w;} int perimeter  () {return  (Length + width)  * 2;} int area  () {return length * width;}}  class square  extends&nBsp rectangle{protected int side; square  (int side) {super (); this.side = side;} int perimeter  () {return 4 * side;} int area  () {return side * side;}}

Those years, learn together Java 4-3