Question

Create, compile and run the JAVA program. Use the methods concepts discussed in the class to develop the program. This assignment is an individual assignment – so has to be done individually by each student. Please submit the JAVA file without any compilation error. Please submit the assignment using blackboard. FYI: - NO USE OF ARRAYS or any type of collection variables. Credit card validation Problem. A credit card number must have between 13 and 16 digits. It must start with: 4 for visa cards 5 for master cards 37 for American express cards 6 for discover cards. This Code must be simple and beginner friendly.

Answer 1

import java.util.*;

public class card {

public static void main(String[] args) {

System.out.println("Enter the card number:");
//Scanner class is used to read the input from user
Scanner s = new Scanner(System.in);
//s.nextLong is used to read long int
//Here long is used because card number must have 13 to 16 digits.To store long number we habe to use long
long num = s.nextLong();
long temp = num;
int NoOfDigits = 0,card_num;
//loop to count the number of digits
//Example temp = 123
//First iteration
//temp = 123/10 = 12
//NoofDigits = NoOfDigits + 1 = 0 + 1 = 1
//Second iteration: temp = 12
//temp = 12 /10 = 1
//NoofDigits = NoOfDigits + 1 = 1 + 1 = 2
//Third iteration: temp = 1
//temp = 1/10 = 0
//NoofDigits = NoOfDigits + 1 = 2 + 1 = 3
//temp > 0 = 0> 0, condition fails.So loop terminated.
//NoOfDigits = 3
while(temp > 0)
{
       temp = temp / 10;
       NoOfDigits = NoOfDigits + 1;
}
//Condition to check NoOfDigits is less than 13 and greater than 16
if(NoOfDigits <13 || NoOfDigits > 16)
{
    System.out.println("Invalid card number.Enter card number digits between 13 to 16.Enter digits are :"+NoOfDigits);
   
}
//if NoOfDigits are in between 13 and 16 this condition will execute.
else
{
    //Math.pow(x,y) - means power of x and y(x^y)
    //To get the first digit of a number we can use below formula
    //Example : num = 123456
    //To get the first digit we have to divide the num with 100000
    //'/' gives the quotient and '^' - power of
    //123456/100000 = 1
    //So num / 10 ^ (digits - 1) gives first digit
    //To get first and second
    //num / 10 ^ (digits - 2)
    //(int) is used to convert to type int and (long) is used convert the type into long
    card_num = (int)(num /(long)Math.pow(10,NoOfDigits-1));
    //condition to check visa card
    if(card_num == 4)
    {
      System.out.println("This card is visa card");
    }
    //condition to check master card
    else if(card_num == 5)
    {
      System.out.println("This card is master card");
    }
    //condition to check discover card
    else if(card_num == 6)
    {
      System.out.println("This card is discover card");
    }
    //condition to check American Express card
    else if(card_num == 3)
    {
      card_num = (int)(num /(long)Math.pow(10,NoOfDigits-2));
     
      if(card_num == 37)
      System.out.println("This card is American express card");

else

  System.out.println("Invalid card.There is no matching digits with given card number");
    }
    //Invalid card number
    else
    {
      System.out.println("Invalid card.There is no matching digits with given card number");
    }
}
}
}

card.java X 3 import java.util.*; 5 public class card { 7 public static void main(String[] args) { 10 11. 12 13 14 16 17 18 System.out.println("Enter the card number:"); //Scanner class is used to read the input from user Scanner s = new Scanner(System.in); //s.nextLong is used to read long int //Here long is used because card number must have 13 to 16 digits. To store long number we habe to use long long num = s.nextLong(); long temp = num; int NoofDigits = 0, card_num; //loop to count the number of digits //Example temp = 123 //First iteration //temp = 123/10 = 12 //NoofDigits = NoOfDigits + 1 = 0 + 1 = 1 //Second iteration: temp = 12 //temp = 12 /10 = 1 //NoofDigits = NoofDigits + 1 = 1 + 1 = 2 //Third iteration: temp = 1 1/temp = 1/10 = 0 //NoofDigits = NoofDigits + 1 = 2 + 1 = 3 [/temp > 0 = 0> 0, condition fails. So loop terminated. 7/NoOfDigits = 3 while(temp > 0) 20 29 temp = temp / 10; NoOfDigits = NoOfDigits + 1;

card.java X 30 31. 32 33 34 35 while(temp > 0) { temp = temp / 10; NoofDigits = NoOfDigits + 1; } [/Condition to check NoOfDigits is less than 13 and greater than 16 if(NoOfDigits <13 || NoOfDigits > 16) { System.out.println("Invalid card number. Enter card number digits between 13 to 16. Enter digits are : "+NoOfDigits); 36 37 40 46 48 49 } //if NoOfDigits are in between 13 and 16 this condition will execute. else { //Math. pow(x,y) - means power of x and y(x^y) //To get the first digit of a number we can use below formula //Example : num = 123456 [/To get the first digit we have to divide the num with 100000 IT'/' gives the quotient and '^' - power of 1/123456/100000 = 1 // So num. 1 10 ^ (digits - 1) gives first digit I/To get first and second //num / 10 ^ (digits - 2) I(int) is used to convert to type int and (long) is used convert the type into long _ card_num= (int) (num / (long)Math.pow(10, NoOfDigits-1)); //condition to check visa card if(card_num == 4) 54. 55

if(card_num == 4) System.out.println("This card is visa card"); // condition to check master card else if(card_num == 5), System.out.println("This card is master card"); // condition to check discover card else if(card_num == 6) System.out.println("This card is discover card"); //condition to check American Express card else if(card_num == 3), card_num = (int) (num (long) Math.pow( 10, NoOfDigits-2));

else if(card_num == 6), System.out.println("This card is discover card"); //condition to check American Express card else if(card_num == 3), card_num = (int) (num / (long)Math.pow(10, NoOfDigits-2)); if(card_num == 37) System.out.println("This card is American express card"); else System.out.println("Invalid card. There is no matching digits with given card number"); //Invalid card number else System.out.println("Invalid card. There is no matching digits with given card number"); 83 } 84. } 85 } 86 }

Enter the card number: 4567891567890123 This card is visa card

Enter the card number: 567891235686789 This card is master card

Enter the card number: 61336789677898 This card is discover card,

Enter the card number: 379890124567898 This card is American express card

Enter the card number: 12345678912345678 Invalid card number. Enter card number digits between 13 to 16. Enter digits are : 17

Enter the card number: 12345678914567 Invalid card. There is no matching digits with given card number