RandomPasswordGenerator.java

import java.util.Random;
import java.util.Scanner;

public class RandomPasswordGenerator {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        Random random = new Random();

        String lowercase = "abcdefghijklmnopqrstuvwxyz";
        String uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        String numbers = "0123456789";
        String special = "!@#$%^&*()-_=+<>?";

        String characters = "";

        System.out.print("Enter password length: ");
        int length = sc.nextInt();

        System.out.print("Include lowercase letters? (yes/no): ");
        String lower = sc.next();

        System.out.print("Include uppercase letters? (yes/no): ");
        String upper = sc.next();

        System.out.print("Include numbers? (yes/no): ");
        String num = sc.next();

        System.out.print("Include special characters? (yes/no): ");
        String spec = sc.next();

        if (lower.equalsIgnoreCase("yes")) {
            characters += lowercase;
        }

        if (upper.equalsIgnoreCase("yes")) {
            characters += uppercase;
        }

        if (num.equalsIgnoreCase("yes")) {
            characters += numbers;
        }

        if (spec.equalsIgnoreCase("yes")) {
            characters += special;
        }

        if (characters.isEmpty()) {
            System.out.println("Error: Select at least one character type.");
        } else {
            String password = "";

            for (int i = 0; i < length; i++) {
                int index = random.nextInt(characters.length());
                password += characters.charAt(index);
            }

            System.out.println("\nGenerated Password: " + password);
        }

        sc.close();
    }
}