CLASS - X : PROGRAM BASED ON CONSTRUCTORS

 PROGRAM BASED ON CONSTRUCTORS

Constructor

Definition 

1. In Java, a constructor is a block of codes similar to the method. 

2. It is called when an instance of the class is created. 

3. At the time of calling constructor, memory for the object is allocated in the memory.

4. It is a special type of method which is used to initialize the object.

5. Every time an object is created using the new keyword, at least one constructor is called.

6. It calls a default constructor if there is no constructor available in the class. 

7. In such case, Java compiler provides a default constructor by default.

8. Types of Java Constructors

There are two types of constructors in Java:

1. Default Constructor (no-arg constructor)

Example:

public class ABC()
{

 int x, y, z;

  ABC()  //default constructor

{

       x=0;

       y=0;

       z=0; 

}}

2. Parameterized Constructor

Example

public class ABC()
{

 int x, y, z;

  ABC(int p. int q, int r)  //Parameterized Constructor

 {

       x=p;

       y=q;

       z=r; 

}}

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ICSE - Computer Application [2023]

Note : this Question was asked as Function Overloading 

But Here Example shows Constructor Overloading

Question 1: Define a class to overload the function print as follows:

void print() - to print the following format

1  1  1  1

2  2  2  2

3  3  3  3

4  4  4  4

5  5  5  5

void print(int n) - To check whether the number is a lead number. A lead number is the one whose sum of even digits are equal to sum of odd digits.

 e.g. 3669

odd digits sum = 3 + 9 = 12

even digits sum = 6 + 6 = 12

3669 is a lead number.

Solution:-

import java.util.Scanner;

public class print

{

    public void print()

    {

        for(int i = 1; i <= 5; i++) 

        {

            for(int j = 1; j <= 4; j++)

            {

                System.out.print(i + " ");

            }

        System.out.println();

        }

    }

    public void print(int n)

    {

        int d = 0;

        int evenSum = 0;

        int oddSum = 0;

        while( n != 0)

        {

            d = n % 10;

            if (d % 2 == 0)

                    evenSum += d;

                else

                    oddSum += d;

            n = n / 10;

        }

        

        if(evenSum == oddSum)

            System.out.println("Lead number");

        else

            System.out.println("Not a lead number");

    }

    

    public static void main(String args[]) 

    {

       Scanner in = new Scanner(System.in);

       System.out.println("Pattern: ");

       System.out.print("Enter a number: ");

        int num = in.nextInt();

        print obj = new print(num);

     }

}