Code for "sam's card"

CardFind.java

import java.util.Scanner;
public class CardFind{
  

  public static void main (String[] args){
    int cardtotal = 52, start = 0000, y, z, thou, hund, ten, one, d_thou, d_ten, total = 0;
    
    while (start < 9999){

    thou = start /1000 ;
    z = start % 1000;
    hund = z /100;
    z = z % 100;
    ten = z / 10;
    one = z % 10;  

    // formatting the thousands row
    if(hund > 4){
    int a_thou = thou*2;
    int a = a_thou / 10;
    int b = a_thou % 10;  
    d_thou = a+b;
    
    } else {
    d_thou = thou*2; 
    }
   

    // formatting the tens row
    if(ten > 4){
    int a_ten = ten*2; 
    int a = a_ten / 10;
    int b = a_ten % 10;  
    d_ten = a+b;
    
    } else {
    d_ten = ten*2; 
    }
   
   
    int testnum = cardtotal+d_thou+hund+d_ten+one;

    if(testnum%10 == 0){
    System.out.println(""+thou+""+hund+""+ten+""+one+"");
    total++;
    }
    
    start++;

    }
    System.out.println("done - in total there were "+total+" total combinations than generated "luhn compliant" numbers");
  }
}