Answer to Question #349290 in Java | JSP | JSF for Ail

Question

Create a Java program that asks the user to input a student number. The format of the student number is a sequence of the following:

Four (4) digits

A dash

Two (2) digits

A dash

Three (3) digits

Display a welcome message if the student number is valid; otherwise, show an appropriate error message. Do not copy the welcome message in the sample output.

Answer 1

import java.util.Scanner;

class Main {
    private static boolean isDigit(char c) {
        return c >= '0' && c <= '9';
    }

    private static boolean isValid(String studentNumber) {
        return studentNumber.length() == 11 &&
                isDigit(studentNumber.charAt(0)) &&
                isDigit(studentNumber.charAt(1)) &&
                isDigit(studentNumber.charAt(2)) &&
                isDigit(studentNumber.charAt(3)) &&
                studentNumber.charAt(4) == '-' &&
                isDigit(studentNumber.charAt(5)) &&
                isDigit(studentNumber.charAt(6)) &&
                studentNumber.charAt(7) == '-' &&
                isDigit(studentNumber.charAt(8)) &&
                isDigit(studentNumber.charAt(9)) &&
                isDigit(studentNumber.charAt(10));
    }

    public static void main(String[] args) {
        try (Scanner scanner = new Scanner(System.in)) {
            System.out.print("Enter a student number: ");
            String studentNumber = scanner.nextLine();
            if (isValid(studentNumber))
                System.out.println("Welcome, student # " + studentNumber);
            else {
                System.out.println("Student number is invalid");
                System.out.println("Valid student number has format XXXX-XX-XXXX (each `X` is a digit)");
            }
        }
    }
}