Authentication.java

package JavaFundamentals;
import java.util.Scanner;
import java.util.ArrayList;

public class HelloWorld {

	public static void main(String[] args) {
		// Authentication for java
		int type;
		boolean isNotLogin = true;
		boolean authenticated = false;
		ArrayList <String> usernames = new ArrayList<>();
		ArrayList <String> passwords = new ArrayList<>();
		String username_input;
		String password_input;
		
		Scanner input = new Scanner(System.in);
		
		while (isNotLogin) {
			
			System.out.print("Would you like to create your account (Press 1 - Signup, 2 - Login) ? " );
			type = input.nextInt();
			input.nextLine();
			
			if (type == 1) {
				System.out.println("Initializing...");
				System.out.println("You can now create your account!");
				System.out.print("Enter your username: ");
				username_input = input.nextLine();
				
				usernames.add(username_input);
				
				System.out.print("Enter your password:  ");
				password_input = input.nextLine();
				
				passwords.add(password_input);
				System.out.println("Sucessfully created your account!");
				
				System.out.println("Heres your account, dont share it with your friends!");
				System.out.println("username: " + username_input);
				System.out.println("password: " + password_input);
			}else if (type == 2) {
				System.out.print("Enter your username: ");
				username_input = input.nextLine();
				
				System.out.print("Enter your password: ");
				password_input = input.nextLine();
				for (int i = 0; i < usernames.size(); i++) {
					if (usernames.get(i).equals(username_input) && passwords.get(i).equals(password_input)) {
						System.out.println("Welcome " + usernames.get(i));
						authenticated = true;
					}
				}
				
				if (!authenticated) System.out.println("Account was not found in the database!");
				else isNotLogin = false;
			}

		}
		
	}
	
	
}