A university student's registration number follows the format:

<CourseCode><Year><CollegeCode><RollNumber>

where

Component	Description
CourseCode	A 3-letter code representing the course (e.g., CSE for Computer Science, ECE for Electronics & Communication)
Year	The last two digits of the admission year.
CollegeCode	A 3-digit code representing the college
RollNumber	A 4-digit unique student roll number.

Examples

Registration Number	Course Code	Admission Year	College Code	Roll Number
CSE240011023	CSE	24	001	1023
ECE252104297	ECE	25	210	4297
ASE230277259	ASE	23	027	7259

Define a class that accepts a student's registration number as input, extracts the relevant details, and displays them in the specified format.

import java.util.Scanner;

public class KboatStuRegNum
{
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter reg. no.: ");
        _______(1)_________
        
        int l = n.length();
        if (l != 12) {
            System.out.println("Invalid reg. no.");
            System.exit(0);
        }   
        
        _______(2)_________
        _______(3)_________
        _______(4)_________
        _______(5)_________
        
        System.out.println("Course Code    : " + cc);
        System.out.println("Admission Year : " + yr);
        System.out.println("College Code   : " + cl);
        System.out.println("Roll Number    : " + rNo);
    }
}

1. String n = in.nextLine();
2. String cc = n.substring(0, 3);
3. String yr = n.substring(3, 5);
4. String cl = n.substring(5, 8);
5. String rNo = n.substring(8);

Explanation

import java.util.Scanner;

public class KboatStuRegNum
{
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter reg. no.: ");
        String n = in.nextLine();
        
        int l = n.length();
        if (l != 12) {
            System.out.println("Invalid reg. no.");
            System.exit(0);
        }   
        
        String cc = n.substring(0, 3);
        String yr = n.substring(3, 5);
        String cl = n.substring(5, 8);
        String rNo = n.substring(8);
        
        System.out.println("Course Code    : " + cc);
        System.out.println("Admission Year : " + yr);
        System.out.println("College Code   : " + cl);
        System.out.println("Roll Number    : " + rNo);
    }
}

Variable Description Table

Program Explanation

Let’s take a closer look at this Java program to understand how it works:

1. Importing Scanner:

• The program starts by importing the java.util.Scanner class, which is used for reading input from the user. The Scanner class is a part of Java's standard library that allows us to capture input from various input sources, including the keyboard.

2. Defining the Main Class & main Method:

• The class is named KboatStuRegNum. It contains the main method which is the entry point of the program. It is where the program begins execution.

3. Reading Input:

• A Scanner object named in is created to capture user input. The program then prompts the user to "Enter reg. no." with System.out.print.

4. Getting the Registration Number:

• Using in.nextLine(), it reads a line of text input from the user and stores it in the String variable n.

5. Validation:

• The program checks if the length of the registration number (n.length()) is exactly 12 characters long. If the length isn't 12, it displays "Invalid reg. no." and terminates the program using System.exit(0). This ensures the input adheres to the expected format.

6. Extracting Information:

• Assuming the input is valid (i.e., 12 characters), the program extracts different parts of the registration number using the substring method:
  • cc: Extracts the first three characters (n.substring(0, 3)) representing the course code.
  • yr: Extracts the next two characters (n.substring(3, 5)) representing the admission year.
  • cl: Extracts characters six to eight (n.substring(5, 8)) which are expected to represent the college code.
  • rNo: Extracts the remaining characters from the ninth to twelfth position (n.substring(8)) which are considered the roll number.

7. Displaying the Components:

• The program then outputs the separated components of the registration number to the console using System.out.println(). This includes:
  • "Course Code : " followed by the extracted course code.
  • "Admission Year : " followed by the extracted admission year.
  • "College Code : " followed by the extracted college code.
  • "Roll Number : " followed by the extracted roll number.

Output