(Credit Card Validation) Credit card numbers follow certain patterns. A credit c

Question

(Credit Card Validation) Credit card numbers follow certain patterns. A credit card number must have between 13 and 16 digits. It must start with:

In 1954, Hans Luhn of IBM proposed an algorithm for validating credit card numbers. The algorithm is useful to determine a card number is entered correctly or whether a credit card is scanned correctly by a scanner. Credit card numbers are generated following this validity check, commonly known as the Luhn check or the Mod 10 check, which can be described as follows (for illustration, consider the card number 4388576018402626);

Write a program that prompts the user to enter a credit card number as a long integer. Display whether the number is valid or invalid

Explanation / Answer

import java.util.Scanner; public class CreditCardValidation { public static boolean isValid(long number) { int total = sumOfDoubleEvenPlace(number) + sumOfOddPlace(number); if ((total % 10 == 0) && (prefixMatched(number, 1) == true) && (getSize(number)>=13 ) && (getSize(number) 0) { temp = number % 100; result += getDigit((int) (temp / 10) * 2); number = number / 100; } return result; } public static boolean prefixMatched(long number, int d) { if ((getPrefix(number, d) == 4) || (getPrefix(number, d) == 5) || (getPrefix(number, d) == 3)) { if (getPrefix(number, d) == 3) { System.out.println(" Visa Card "); } else if (getPrefix(number, d) == 5) { System.out.println(" Master Card "); } else if (getPrefix(number, d) == 3) { System.out.println(" American Express Card "); } return true; } else { return false; } } public static int getSize(long d) { int count = 0; while (d > 0) { d = d / 10; count++; } return count; } public static long getPrefix(long number, int k) { if (getSize(number)

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