This Program is written in Java, I am not sure what direction to go with this pr
ID: 3662459 • Letter: T
Question
This Program is written in Java, I am not sure what direction to go with this program.
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
• 37 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 whether 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):
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. 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
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.
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. Design your program to use the following methods:
Explanation / Answer
/**
* @author Srinivas Palli
*
*/
public class CreditCardValidator {
/**
* @param number
* @return
*/
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) <= 16)) {
return true;
} else {
return false;
}
}
/**
* @param number
* @return
*/
public static int getDigit(int number) {
if (number <= 9) {
return number;
} else {
int firstDigit = number % 10;
int secondDigit = (int) (number / 10);
return firstDigit + secondDigit;
}
}
/**
* @param number
* @return
*/
public static int sumOfOddPlace(long number) {
int result = 0;
while (number > 0) {
result += (int) (number % 10);
number = number / 100;
}
return result;
}
/**
* @param number
* @return
*/
public static 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;
}
/**
* @param number
* @param d
* @return
*/
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;
}
}
/**
* @param d
* @return
*/
public static int getSize(long d) {
int count = 0;
while (d > 0) {
d = d / 10;
count++;
}
return count;
}
/**
* @param number
* @param k
* @return
*/
public static 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;
}
}
/**
* @param args
*/
public static void main(String[] args) {
long input = 4388576018410707l;
if (isValid(input) == true) {
System.out.println(" " + input + " is Valid. ");
} else {
System.out.println(" " + input + " is Invalid. ");
}
input = 4388576018402626l;
if (isValid(input) == true) {
System.out.println(" " + input + " is Valid. ");
} else {
System.out.println(" " + input + " is Invalid. ");
}
}
}
OUTPUT:
4388576018410707 is Valid.
4388576018402626 is Invalid.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.