rule for using the super keyword

[javastuden]

hi
what are the rule for using the super keyword
do that be the first in any and where it be in the class(child) please explain in detail with example

thanks in advance

[JosAH]

hi
what are the rule for using the super keyword
do that be the first in any and where it be in the class(child) please explain in detail with example

Every text book explains it in great detail. Do you have one? If so, read it.

kind regards,

Jos

[j2me64]

please explain in detail with example

ok, i wrote a small example that shows two rules of super. the first rule is concerning the constructors and the second rule is concerning how to refer variables with the same name. look at the comments in the code.

class Parent {
	private String name;
	public int nr;

	public Parent(String n) {
		this.name = n;
		nr = 10;
	}
}

public class Child extends Parent {
	// since the Parent has no default constructor
	// the first statement in the constructor of the Child class must
	// be a call to the non default constructor
	// otherwise you will get an error like
	// "Constructor call must be the first statement in a constructor"
	public Child(String n, int nr) {
		super(n);
		this.nr = nr;
	}

	// the Child class has a variable with the same name like
	// its parent, so to refer the parent variable use super and
	// the current variable use this
	private int nr;

	public int getParentNr() {
		// super refer the Parent Object
		return super.nr;
	}

	public int getChildNr() {
		// this means the current object
		return this.nr;
	}

	public static void main(String[] args) {
		Child c = new Child("Child", 5);
		System.out.println("from the Parent class nr = " + c.getParentNr());
		System.out.println("from the child class nr = " + c.getChildNr());
	}
}]

i hope, you can use the code as starting point for super.