Method for Cedit card check, help!!!!1

2. Write a program to determine whether an input credit number is valid according to the Luhn check. Prompt the user for a credit card number as a long integer and display whether the number is valid.

Need help creating a method for this process, im unsure how to check a set of long numbers and iterate the steps. Please help me with.........

The Luhn check is performed as follows:



Step 1: Double every second digit from the right to the left. If doubling of a digit results in a two-digit number, add up the two digits to get a single-digit number.

Step 2: Now add all single-digit numbers from Step 1.

Step 3: Add all the digits in the odd places from right to left in the card number.

Step 4: Sum the results from Step 2 and Step 3.

Step 5: If the result from Step 4 is divisible by 10, the card number is valid; otherwise it is invalid.

What exactly do you need help with (what have you done)?

I take it this is an assignment, however if its not, how about Validator - Commons Validator

// Json

Im stuck on how to create methods for the sumofodd/even places method. What i have is below....:-t:-t

Code :

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import javax.swing.JOptionPane;
import java.util.Scanner;
 
public class CreditCard{
public static void main(String [] args){
 
Scanner input = new Scanner(System.in);
 
System.out.println("Enter your credit card number: ");
long number = input.nextLong();
 
System.out.println("Your credit card number is: " + number);
 
if (isValid(number)){
	System.out.println("The credit card number\n " + number + " is a valid");
}
else
	System.out.println("The credit card is not valid");		
}
public static boolean isValid(long number){
	long sumOdd = sumOddPlaces (number);
	long sumEven = sumEvenPlaces (number);
 
	if(sumOdd + sumEven % 10 == 0){
		return true;
	}
	else{
		return false;
}
}
 
public static int getDigit(int number){
	if(number < 10)
		return number;
 
	else{
	int d2 = number % 10;
	int d1 = number / 10;
 
	return d2 + d1;
	}
 
public static int sumOfEvenPlaces(long number){
   String str_prime = (new Integer(number)).toString();
   int lastIndex = str_prime.length()-1;
   	for (i =0; i <= lastIndex - 2; i--){
			if(   ) 
 
 
}
 
 
public static in sumOfOddPlaces(long number){

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Here are the two methods i need names i need to make......

Code :

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// Get the result from Step 2
 
      public static int sumOfEvenPlace(long number)
 
 // Return the sum of the odd place digits in number
 
      public static int sumOfOddPlace(long number)

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My first question would be, can a credit card number start with a zero?

If so, you need to capture it as a string rather than a long.

Second of all I'd suggest you use a string anyway and loop through each caracter and extract ever odd one and sum them up.

// Json

can you show me an example my professor has not covered that material yet...

Here's one way to see if a number is even or odd.

Code :

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if (n % 2 == 0)
  // n is even
else
  // in is odd

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