# Credit Card Validator

Easy
14
1
70.6% Acceptance

In this lab, you will be implementing the `validateCreditCard` method in Java. The method should utilize the Luhn algorithm to determine the validity of a given credit card number.

### Instructions

1. Implement `validateCreditCard` method:

• Open the `Main` class.
• Implement the `validateCreditCard` method using the provided signature:
``````public static boolean validateCreditCard(String creditCardNumber) {
}``````
• Your method should return `true` for a valid credit card number.
2. Handle invalid credit card numbers:

• Extend the `validateCreditCard` method to handle invalid credit card numbers.
• Update the method to return `false` when an invalid credit card number is provided.
• Ensure the method still returns `true` for a valid credit card number.

### Luhn Algorithm

The Luhn algorithm is a simple checksum formula that is used to validate various identification numbers, including credit card numbers. Here's a brief overview:

1. Starting from the rightmost digit, double every second digit.
2. If doubling results in a two-digit number, add the digits together.
3. Sum all the digits in the credit card number.
4. If the total sum is a multiple of 10, the credit card number is valid.

### Expected Output

• Challenge 1: Your `validateCreditCard` method should return `true` for a valid credit card number.
• Challenge 2: The method should return `false` for an invalid credit card number.

### Tips

• Pay attention to the Luhn algorithm logic.
• Test your code thoroughly with different credit card numbers.

### Challenges

Challenge 1: Implement the `validateCreditCard` method

Implement the `validateCreditCard` method in the `Main` class in Java. The method should use the Luhn algorithm to check the validity of a given credit card number. The method should be defined as follows:

Ensure that the method returns `true` for a valid credit card number.

Challenge 2: Handle invalid credit card numbers

Extend the `validateCreditCard` method to handle invalid credit card numbers. Update the method to return `false` when an invalid credit card number is provided. Ensure that the method still returns `true` for a valid credit card number.