MUST IMPLEMENT at least 4 of the 7 METHODS LISTED IN THE BOOK!!!! Credit card nu
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Question
MUST IMPLEMENT at least 4 of the 7 METHODS LISTED IN THE BOOK!!!!
Credit card numbers follow certain patterns. A credit card number must have 16 digits. It must start with:
4 for Visa cards
5 for Master 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
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.
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
Analysis: TAKE AS MUCH SPACE AS NEEDED FOR THESE EXPLANATIONS.
(Describe the problem including input and output in your own words. If a class structure is used turn in the UML design)
Design:
(Describe the major steps for solving the problem using the diagram like the one in the book Figure 6.11, page 228)
Testing: (Describe how you test this program). Attach printed outputs of at least 5 different test runs (must contain test cases for Visa, Master, Discover cards, valid or invalid).
Coding: Attach a printed copy of your program WITH OUTPUT as last pages of this document.
Explanation / Answer
algorithm for validating credit card
import java.util.Scanner;
public class ValidCard
{
public static void main(String[] args) {
Scanner in = new Scanner(System.in); //Scanner to read input from user
System.out.print("Enter your Credit Card Number : ");
String inString = in.next(); //To read input from user
int sum = 0; //Declare and initialize sum to zero.
boolean alternate = false; //To process alternate digits or Double every second digit
for (int i = inString.length() - 1; i >= 0; i--) //To process from right to left
{
int n = Integer.parseInt(inString.substring(i, i + 1)); //Takes each digit from right to left
if (alternate) // initially alternate=false, will change the status for next digit
{
n *= 2;
if (n > 9) //For two digit number
{
n = (n % 10) + 1; //To Add the digits in the number
}
}
sum += n; //Sums the values
alternate = !alternate; //Change status of alternate,if false, set alternate=true and vise versa.
}
if (sum % 10 == 0) //If the result or sum is divisible by 10, the card number is valid
{
System.out.println("Valid Card!");
}
else
{
System.out.println("The Credit Card Number is Invalid!");
}
}
}
This code is written in java. If you use another language like c,c++ you can change it accordingly.
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