1.For some reason I am getting this error on my code.

Error: Main method not found in class CreditCard, please define the main method as: public static void main(String[] args) or a JavaFX application class must extend javafx.application.Application

import java.util.Scanner;

public class CreditCard{

/** Return true if the card number is valid */

public static boolean isValid(long number){

return (getSize(number) >= 13 &&

getSize(number) <= 16) &&

(prefixMatched(number, 4) ||

prefixMatched(number, 5) ||

prefixMatched(number, 37) ||

prefixMatched(number, 6)) &&

((sumOfDoubleEvenPlace(number) +

sumOfOddPlace(number)) % 10 == 0);

}

/** Get the result from Step 2 */

public static int sumOfDoubleEvenPlace(long number){

int sum = 0;

String num = number + "";

for (int i = getSize(number) - 2; i >= 0; i -= 2)

sum += getDigit(Integer.parseInt(num.charAt(i) + "") * 2);

return sum;

}

/** Return this number if it is a single digit, otherwise,

* return the sum of the two digits */

public static int getDigit(int number){

if (number < 9)

return number;

return number / 10 + number % 10;

}

/** Return sum of odd-place digits in number */

public static int sumOfOddPlace(long number){

int sum = 0;

String num = number + "";

for (int i = getSize(number) - 1; i >= 0; i -= 2)

sum += Integer.parseInt(num.charAt(i) + "");

return sum;

}

/** Return true if the digit d is a prefix for number */

public static boolean prefixMatched(long number, int d){

return getPrefix(number, getSize(d)) == d;

}

/** Return the number of digits in d */

public static int getSize(long d){

String num = d + "";

return num.length();

}

/** Return the first k number of digits from number. If the

* number of digits in number is less than k, return number. */

public static long getPrefix(long number, int k){

if (getSize(number) > k) {

String num = number + "";

return Long.parseLong(num.substring(0, k));

}

return number;

}

/** input credit cards number from keyboard

Return this credit Cards number

*/

public static void inputData(){

Scanner input = new Scanner(System.in);

System.out.print("Please input your credit card number: ");

long number = input.nextLong();

if(isValid(number))

System.out.println(number + " is valid.");

else

System.out.println(number + " is not valid.");

}

/**

Display result using a method println()

*/

public static void displayResult(long number){

}

}

.2. C++ discussion Assignment

Share a short program to illustrate pointers.Explain.