PrimeNumberRange.java

import java.util.Scanner;

class PrimeRangeAnalyzer {
    private int startRange;
    private int endRange;
    private int primeCount;
    private long primeSum;

    // Constructor to initialize and validate the range
    public PrimeRangeAnalyzer(int start, int end) {
        if (start > end) {
            System.out.println("Notice: Start value is greater than End value. Swapping them.");
            this.startRange = end;
            this.endRange = start;
        } else {
            this.startRange = start;
            this.endRange = end;
        }
        this.primeCount = 0;
        this.primeSum = 0;
    }

    // Private helper method to check if a single number is prime
    private boolean isPrime(int n) {
        if (n <= 1) {
            return false;
        }
        for (int i = 2; i <= Math.sqrt(n); i++) {
            if (n % i == 0) {
                return false;
            }
        }
        return true;
    }

    // Method to calculate the sum and count of primes in the range
    public void calculate() {
        for (int i = startRange; i <= endRange; i++) {
            if (isPrime(i)) {
                primeCount++;
                primeSum += i;
            }
        }
    }

    // Method to display the final results
    public void displayResults() {
        System.out.println("\n--- Prime Number Analysis ---");
        System.out.println("Range: " + startRange + " to " + endRange);
        System.out.println("Total Prime Numbers Found: " + primeCount);
        System.out.println("Sum of all Prime Numbers: " + primeSum);
        System.out.println("-----------------------------");
    }
}

// Main Driver Class
public class PrimeNumberRange {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        System.out.println("--- Prime Number Range Calculator ---");
        System.out.print("Enter the starting number of the range: ");
        int start = getValidInt(scanner);

        System.out.print("Enter the ending number of the range: ");
        int end = getValidInt(scanner);

        // Instantiate the object and run the methods
        PrimeRangeAnalyzer analyzer = new PrimeRangeAnalyzer(start, end);
        analyzer.calculate();
        analyzer.displayResults();

        scanner.close();
    }

    // Helper method to prevent scanner crashes on invalid input
    private static int getValidInt(Scanner scanner) {
        while (!scanner.hasNextInt()) {
            System.out.print("Invalid input. Please enter a valid whole number: ");
            scanner.next();
        }
        return scanner.nextInt();
    }
}