what is constructor chaining ?????

explain with example in detail how to solve it program plz send a program

Anirudha
16 May
4109 Views
8 Answers

Satishkumar
25 Apr

1.Constructor chaining is the process of calling one constructor from another constructor with respect to current object. 2.Constructor chaining can be done in two ways: &nbsp;a).Within same class: It can be done using this() keyword for constructors in same class b).From base class: by using super() keyword to call constructor from the base class. --&gt;Constructor chaining occurs through inheritance. A sub class constructor&rsquo;s task is to call super class&rsquo;s constructor first. This ensures that creation of sub class&rsquo;s object starts with the initialization of the data members of the super class. There could be any numbers of classes in inheritance chain. Every constructor calls up the chain till class at the top is reached. // Java program to illustrate Constructor Chaining // within same class Using this() keyword class Temp { &nbsp;&nbsp;&nbsp;&nbsp;// default constructor 1 &nbsp;&nbsp;&nbsp;&nbsp;// default constructor will call another constructor &nbsp;&nbsp;&nbsp;&nbsp;// using this keyword from same class &nbsp;&nbsp;&nbsp;&nbsp;Temp() &nbsp;&nbsp;&nbsp;&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// calls constructor 2 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;this(5); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;System.out.println(&quot;The Default constructor&quot;); &nbsp;&nbsp;&nbsp;&nbsp;} &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;// parameterized constructor 2 &nbsp;&nbsp;&nbsp;&nbsp;Temp(int x) &nbsp;&nbsp;&nbsp;&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// calls constructor 3 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;this(5, 15); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;System.out.println(x); &nbsp;&nbsp;&nbsp;&nbsp;} &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;// parameterized constructor 3 &nbsp;&nbsp;&nbsp;&nbsp;Temp(int x, int y) &nbsp;&nbsp;&nbsp;&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;System.out.println(x * y); &nbsp;&nbsp;&nbsp;&nbsp;} &nbsp; &nbsp;&nbsp;&nbsp;&nbsp;public static void main(String args[]) &nbsp;&nbsp;&nbsp;&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// invokes default constructor first &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;new Temp(); &nbsp;&nbsp;&nbsp;&nbsp;} } Output: The Default constructor 5 75

Cancel

1.Constructor chaining is the process of calling one constructor from another constructor with respect to current object.
2.Constructor chaining can be done in two ways:
a).Within same class: It can be done using this() keyword for constructors in same class
b).From base class: by using super() keyword to call constructor from the base class.
-->Constructor chaining occurs through inheritance.
A sub class constructor’s task is to call super class’s constructor first. This ensures that creation of sub class’s object starts with the initialization of the data members of the super class. There could be any numbers of classes in inheritance chain. Every constructor calls up the chain till class at the top is reached.
// Java program to illustrate Constructor Chaining
// within same class Using this() keyword
class Temp
{
    // default constructor 1
    // default constructor will call another constructor
    // using this keyword from same class
    Temp()
    {
        // calls constructor 2
        this(5);
        System.out.println("The Default constructor");
    }

    // parameterized constructor 2
    Temp(int x)
    {
        // calls constructor 3
        this(5, 15);
        System.out.println(x);
    }

    // parameterized constructor 3
    Temp(int x, int y)
    {
        System.out.println(x * y);
    }

    public static void main(String args[])
    {
        // invokes default constructor first
        new Temp();
    }
}
Output:
The Default constructor
5
75

0 Comments
Share

0

Other Related Discussions