Hans Luhn Algorithm Algorithm Description: Credit card numbers follow certain pa
ID: 3774960 • Letter: H
Question
Hans Luhn Algorithm Algorithm Description: Credit card numbers follow certain patterns. A credit card number must have between 13 and 16 digits. It must start with: 4 for Visa cards 5 for Master cards 36 for American Express cards 6 for Discover cards In 1954, Hans Luhn of IBM proposed an algorithm for validating credit card numbers. The algorithm is useful to determine if a card number is entered correctly or if a credit card is scanned correctly by a scanner. Almost all 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):
1. Double every second digit from right to left. If doubling of a digit results in a two-digit number, add up the two digits to get a single-digit number. 2 * 2 = 4 2 * 2 = 4 4 * 2 = 8 1 * 2 = 2 6 *
2 = 12 (1 + 2 = 3) 5 * 2 = 10 (1 + 0 = 1) 8 * 2 = 16 (1 + 6 = 7) 4 * 2 = 8
2. Now add all single-digit numbers from Step 1. 4 + 4 + 8 + 2 + 3 + 1 + 7 + 8 = 37
3. Add all digits in the odd places from right to left in the card number. 6 + 6 + 0 + 8 + 0 + 7 + 8 + 3 = 38 MIS 2845 – Section 001 Group Project Spring 2016 2
4. Sum the results from Step 2 and Step 3. 37 + 38 = 75 5. If the result from Step 4 is divisible by 10, the card number is valid; otherwise, it is invalid. For example, the number 4388576018402626 is invalid, but the number 4388576018410707 is valid. Here are sample runs of the program: Sample 1: Enter a credit card number as a long integer: 4246345689049834 4246345689049834 is invalid Sample 2: Enter a credit card number as a long integer: 4388576018410707 4388576018410707 is valid MIS 2845 – Section 001 Group Project Spring 2016 3
Project Part II
(The Account class) Design a class named Account that contains: • A long integer data field named accoutNumber for the account (default 0). • A no-arg constructor that creates a default account. • A constructor that creates an account with the specified accoutNumber. • A method named accountType(Long number) that returns a boolean. The method determines if the account type is a credit card. The method will use the CardValidation class to check if the account number passed in the method is a valid credit card number. If it is not then the method returns True.
(The CardValidation class) Design a class named CardValidation that contains: • A long integer data field named cardNumber for the account (default 0). • A no-arg constructor that creates a default CardValidation. • A constructor that creates an account with the specified cardNumber. • A static method named isValid(long cardNumber) that returns a Boolean.(True or False) The method determines if the card number is a valid credit card number. The method will return true if the card number is valid. The method will use the Hans Luhn logarithm. Almost all credit card numbers are generated following this validity check, commonly known as the Luhn check or the Mod 10 check. The logarithm is explained above in Part I pf the project.
I Need help with the account class and card validation class in the project part II of this question.
Explanation / Answer
public class Account {
private long accoutNumber;
public Account() {
// TODO Auto-generated constructor stub
accoutNumber = 0;
}
/**
* @param accoutNumber
*/
public Account(long accoutNumber) {
this.accoutNumber = accoutNumber;
}
public boolean accountType() {
int total = sumOfDoubleEvenPlace(accoutNumber) + sumOfOddPlace(accoutNumber);
if ((total % 10 == 0) && (prefixMatched(accoutNumber, 1) == true)
&& (getSize(accoutNumber) >= 13) && (getSize(accoutNumber) <= 16)) {
return true;
} else {
return false;
}
}
/**
*
* @param number
* @return
*/
private int sumOfDoubleEvenPlace(long number) {
int result = 0;
long temp = 0;
while (number > 0) {
temp = number % 100;
result += getDigit((int) (temp / 10) * 2);
number = number / 100;
}
return result;
}
/**
* Return this number if it is a single digit, otherwise, return the sum of
* the two digits
*
* @param number
* @return
*/
private int getDigit(int number) {
if (number <= 9) {
return number;
} else {
int firstDigit = number % 10;
int secondDigit = (int) (number / 10);
return firstDigit + secondDigit;
}
}
public void main(String[] args) {
}
/**
* Return sum of odd place digits in number
*
* @param number
* @return
*/
public int sumOfOddPlace(long number) {
int result = 0;
while (number > 0) {
result += (int) (number % 10);
number = number / 100;
}
return result;
}
/**
* Return true if the digit d is a prefix for number
*
* @param number
* @param d
* @return
*/
public 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;
}
}
/**
* Return the first k number of digits from number. If the * number of
* digits in number is less than k, return number.
*
* @param number
* @param k
* @return
*/
public long getPrefix(long number, int k) {
if (getSize(number) < k) {
return number;
} else {
int size = (int) getSize(number);
for (int i = 0; i < (size - k); i++) {
number = number / 10;
}
return number;
}
}
/**
* Return the number of digits in d
*
* @param d
* @return
*/
public int getSize(long d) {
int count = 0;
while (d > 0) {
d = d / 10;
count++;
}
return count;
}
}
import java.util.Scanner;
public class CardValidation {
/**
* @param args
*/
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Please enter a Credit Card Number: ");
long input = sc.nextLong();
if (isValid(input) == true) {
System.out.println("The CC Number: " + input + " is Valid. ");
} else {
System.out.println("The CC Number: " + input + " is Invalid. ");
}
}
/**
* @param cardNumber
* @return
*/
public static boolean isValid(long cardNumber) {
Account account = new Account(cardNumber);
return account.accountType();
}
}
OUTPUT:
Please enter a Credit Card Number: 4388576018410707
The CC Number: 4388576018410707 is Valid.
Please enter a Credit Card Number: 4246345689049834
The CC Number: 4246345689049834 is Invalid.
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