Question

Please answer in Visual Studio 2019 c# format. Not python. Thank you.

Q. Write a program that works as described in the following scenario: The user enters a credit card number. The program displays whether the credit card number is valid or invalid. Here are two sample runs: Enter a credit card number as a long integer: 4388576018410707 4388576018410707 is valid Enter a credit card number as a long integer: 4388576018402626 4388576018402626 is invalid To check the validity of the card number, you need to use the Luhn check or the Mod 10 check algorithm, which is described below. Assume the card number is 4388576018402626. 1. Double every second digit from right to left. If doubling of a digit results in a two-digit number, add up the two digits to get a single-digit number. 4388576018402626 2 * 2 = 4 ► 2*2=4 4*2 = 8 1*2= 2 → 6* 2 = 12 (1 + 2 = 3) → 5* 2 = 10 (1 + 0 = 1) → 8* 2 = 16 (1 + 6 = 7) 4*2 = 8 2. Now add all single-digit numbers from Step 1. 4+4+8+2+3+1+7+ 8 = 37

Answer 1

using System;
class Card {
static long card_num;
static int e_sum=0,o_sum=0;
static void Main()
{
//read the card number from the user
Console.WriteLine("Enter the card number :");
card_num = Convert.ToInt64(Console.ReadLine());
//check Isvalid() function
if(Isvalid(card_num)==true)
{
Console.WriteLine("Valid");
}
else
{
Console.WriteLine("Invalid");
}
}
//returns the size of the number passed
public static int GetSize(long d)
{
return d.ToString().Length;
}
//gets the prefix
public static long GetPrefix(long number,int k)
{
string x=number.ToString();
if(x.Length>k-1)
{
x=x.Substring(0,k);
long y=long. Parse(x);
return y;
}
else
{
return number;
}

}
public static bool PrefixMatched(long number,int d)
{
//here a default prefix value of lenth 4 is passed
long x=GetPrefix(438857,4);
//reads prefix of user inputed card number
long y=GetPrefix(number,d);
//if both are same returns true else false
if(x==y)
{
return true;
}
else
{
return false;
}
}
//checks the pased number is two digit or not if yes finds the sum of it's two digits
public static int GetDigit(int number)
{
int x;
if(number>9)
{
x=(number/10)+(number%10);
}
else
{
x=number;
}
return x;
}
//returns the sum of even place
public static int SumOfDoubleEvenPlace(long number)
{
e_sum=e_sum+Convert.ToInt32(number);
return e_sum;
}
//returns the sum of odd place
public static int SumOfOddPlace(long number)
{
o_sum=o_sum+Convert.ToInt32(number);
return o_sum ;
}
public static bool Isvalid(long number)
{
//initially checks the prefix if true executes following else return false for Isvalid()
if((PrefixMatched(card_num,4))==true)
{
string check=card_num.ToString();
for(int i=(GetSize(card_num)-1);i>=0;i--)
{
if(i%2==0)
{
e_sum=(SumOfDoubleEvenPlace(Convert.ToInt64(GetDigit(Convert.ToInt32(2*((check[i])-'0'))))));
}
else
{
o_sum=(SumOfOddPlace(Convert.ToInt64(GetDigit(Convert.ToInt32(((check[i])-'0'))))));
}
}
if((e_sum+o_sum)%10==0)
{
return true;
}
else
{
return false;
}
  
}
else
{
return false;
}
}
}

OUTPUT

Enter the card number :
4388576018410707
Valid

4 5 1e 14 17 18 19 20 1 using System; 2. class Card { 3 static long card_num; static int e_sum=2,0_sum=e; static void Main() 6 { 7 //read the card number from the user 8 Console.WriteLine("Enter the card number :"); 9 card_num = Convert.ToInt64(Console.ReadLine()); //check Isvalido) function 11 if(Isvalid(card_num==true)|| 12 { 13 Console.WriteLine("Valid"); } 15 else 16 { Console.WriteLine("Invalid"); } } 1/returns the size of the number passed 21 public static int GetSize(long d) 22 { 23 return d.ToString().length; 24 25 1/gets the prefix 26 public static long GetPrefix( long number, int k) 27 { 28 string x=number.ToString(); if(x.Length>k-1) { 31 x=x. Substring(@,k); 32 long y=long. Parse(x); 33 return y; 34 35 else { return number; 38 } 39 40 } public static bool PrefixMatched (long number, int d) 42 43 1/here a default prefix value of Lenth 4 is passed long x=GetPrefix(438857,4); //reads prefix of user inputed card number long y=GetPrefix(number,d); 47 //if both are same returns true else false if(x==y) { 29 30 36 37 41 45 46 48 49

49 50 51 52 53 54 55 56 57 58 59 62 61 62 63 64 65 66 67 68 69 7e 71 72 73 74 75 76 77 78 79 se 81 82 83 84 85 86 87 { return true; } else { return false; } } 1/checks the pased number is two digit or not if yes finds the sum of it's two digits public static int GetDigit(int number) { int x; if(number>9){ X=(number/10)+(number10); } else{ X=number; } return x; } 1/returns the sum of even place public static int SumofDoubleEvenPlace(long number) { e_sum e_sum-Convert.ToInt32 (number); return e_sum; } 1/returns the sum of odd place public static int SumofoddPlace(long number) { o_sum-o_sum Convert.ToInt32(number); return o_sum ; } public static bool Isvalid(long number) { //initially checks the prefix if true executes following else return false for Isvalido) if((PrefixMatched (card_num,4))==true) { string check=card_num.ToString(); for(int i=(GetSize(card_num)-1);i>=0;i--) { if(i%2==0) { e_sum=(SumofDoubleEvenPlace(Convert.ToInt64(GetDigit(convert.ToInt32(2*((check[i])-'")))))); else { o_sum=(SumofoddPlace(Convert.ToInt64(GetDigit(Convert.ToInt32(((check[i])-'0')))))); } } 89 98 91 92 93 94 95 96 97

94 95 96 97 98 99 lee 101 102 183 184 1e5 186 107 188 109 110 111 112} { o_sum=(SumofoddPlace(Convert.ToInt64(GetDigit(Convert.ToInt32(((check[i])-'@')))))); } } if((e_sumo_sum)X10-20) { return true; } else { return false; } } else { return false; } }

Enter the card number : 4388576018410707 Valid