Creditcrdnum_valid_checker.java

package PraticeProblems; //to make this program as package
import java.util.*;
public class creditCardValidation { //to compile in online just give public class Main
  public static boolean validation(long credit_number) {
    return (sizecheck(credit_number)>= 13 && sizecheck(credit_number) <= 16 &&
        (prefixcheck(credit_number, 4) || prefixcheck(credit_number, 5) || 
            prefixcheck(credit_number, 37) || prefixcheck(credit_number, 6)) &&
        (sumOfEven(credit_number)+sumOfOdd(credit_number)) % 10 == 0);
  }
  public static int sizecheck(long c_num) {
    String num = c_num+"";
    return num.length();
  }
  public static boolean prefixcheck(long c_num, int d) {
    return getprefix(c_num, sizecheck(d)) == d;
  }
  public static long getprefix(long c_num, int k) {
    if(sizecheck(c_num)>k) {
      String num = c_num + "";
      return Long.parseLong(num.substring(0, k));
    }
    return c_num;
  }
  public static int sumOfOdd(long c_num) {
    int sum = 0;
    String num = c_num + "";
    for(int i = sizecheck(c_num)-1; i >= 0; i -= 2) {
      sum += Integer.parseInt(num.charAt(i)+"");
    }
    return sum;
  }
  public static int sumOfEven(long c_num) {
    int sum = 0;
    String num = c_num + "";
    for(int i = sizecheck(c_num)-1; i >= 0; i -= 2) {
      sum += getDigit(Integer.parseInt(num.charAt(i)+""));
    }
    return sum;
  }
  public static int getDigit(int num) {
    if(num<9)
      return num;
    return num/10 + num%10;
  }
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long credit_number;
    System.out.print("Enter credit card number: ");
    credit_number = sc.nextLong();
    sc.close();
    System.out.println(credit_number + " is "+ (validation(credit_number) ? "valid":"invalid"));
    /*if(prefixcheck(credit_number, 4)){
      System.out.print("The given credit card is visa card");
    }else if(prefixcheck(credit_number, 5)){
      System.out.print("The given credit card is master card");
    }else if(prefixcheck(credit_number, 6)){
      System.out.print("The given credit card is discover card");
    }else if(prefixcheck(credit_number, 37)){
      System.out.print("The given credit card is american express card");
    }else {
      System.out.print("The given credit card is does not belong given any given class");
    }*/
//     INCLUDE ABOVE COMMENT PROGRAM IF YOU NEED TO SEE WHAT CARD IS IT 
//     OR LEAVE JUST TO SEE VALID OR NOT
  }
}



                                                     //OR//THIS SECOND PART IS FOR EDUCATIONAL PORTAL PROBLEM STATEMENT (SOLUTION)
/*import java.util.Scanner; 
 class CreditCard { 
 
    public static void main(String[] args) 
    { 
    	Scanner myObj =new Scanner(System.in);
    	long number = myObj.nextLong(); 
  
        System.out.println(number + " is " +  
        (isValid(number) ? "valid" : "invalid")); 
    } 
  
    
    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); 
    } 
  
    // 
    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; 
    } 

    public static int getDigit(int number) 
    { 
        if (number < 9) 
            return number; 
        return number / 10 + number % 10; 
    } 
  
  
    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; 
    } 
  
   
    public static boolean prefixMatched(long number, int d) 
    { 
        return getPrefix(number, getSize(d)) == d; 
    } 
  

    public static int getSize(long d) 
    { 
        String num = d + ""; 
        return num.length(); 
    } 
  
 
    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                                OUTPUT
5196081888500645           5196081888500645 is valid
1234567890123456           1234567890123456 is invalid
*/