Question

Please write the code in C++. This is all one question with multiple requirements.

1) Create an enumerated data type called CrdCard

The types of Credit Cards to create are all 16 digits long except American Express: American Express (34 or 37), Visa (Starts with a 4), MasterCard (Starts with 51-55), Discover (Starts with 6011).

2) Create a function that takes in the enumerated type and returns a valid credit card number using the

Luhn Algorithm (also called the Modulus 10 Algorithm:

From the rightmost digit, which is the check digit, moving left, double the value of every second digit; if the product of this doubling operation is greater than 9 (e.g., 7 * 2 = 14), then sum the digits of the products (e.g., 10: 1 + 0 = 1, 14: 1 + 4 = 5).

Take the sum of all the digits. If the total modulo 10 is equal to 0 (if the total ends in zero) then the number is valid according to the Luhn formula; else it is not valid.

Assume an example of an account number "7992739871" that will have a check digit added, making it of the form 7992739871x:

Account number	7	9	9	2	7	3	9	8	7	1	x
Double every other	7	18	9	4	7	6	9	16	7	2	x
Sum of digits	7	9	9	4	7	6	9	7	7	2	=67

The check digit (x) is obtained by computing the sum of digits then computing 9 times that value modulo 10 (in equation form, (67 * 9 mod 10)). In algorithm form:

Compute the sum of the digits (67).

Multiply by 9 (603).

The last digit, 3, is the check digit.).

Note: Length, etc... are dependent on credit card type.

genCC(CrdCard,char []), or

char *genCC(CrdCard)

3) Create a function that randomly flips only 2 digits. (Randomizes any two digits that are not the identifying number for the card carrier ie. 4 for Visa 51-55 for Mastercard etc. and not the last digit or else it will invalidate the Luhn)

void flipDig(char []);

4) Create a function that transposes only 2 digits (Randomizes two digits that are next to each other and are not the identifying number for the card carrier ie. 4 for Visa 51-55 for Mastercard etc. and not the last digit or else it will invalidate the Luhn)

5) Create a function that determines if the result is a valid Credit Card

bool validCC(char[]);

6) Loop 10,000 times and record how many valid vs. invalid Credit Cards are detected for 3) and 4)

Answer 1

The required code is given below in case of any doubts please ask me in comments and please do upvote.

main.cpp

#include<bits/stdc++.h>
using namespace std;
int len;
char num[16];   
enum CrdCard {AmericanExpress, Visa, MasterCard, Discover};   
char* genCC(CrdCard card){
int sum;
if(card == AmericanExpress){
len = 15;
}else{
len = 16;   
}
switch(card){
case AmericanExpress:   
num[0]=3+48;
(rand()%2)?(num[1]=4+48):(num[1]=7+48);
for(int i=2;i<len-1;i++){
num[i] = 48 + rand()%10;
}
for(int i=len-3;i>=2;i=i-2){
int n = (num[i]-'0') * 2;
if(n>9){
n = (n/10) + (n%10);
}
num[i] = n + 48;
}
for(int i=0;i<len-1;i++){
sum += num[i];
}
num[len-1] = 48 + (sum*9)%10;
break;
case Visa:
num[0]=4+48;
for(int i=1;i<len-1;i++){
num[i] = 48 + rand()%10;
}
for(int i=len-3;i>=1;i=i-2){
int n = (num[i]-'0') * 2;
if(n>9){
n = (n/10) + (n%10);
}
num[i] = n + 48;
}
for(int i=0;i<len-1;i++){
sum += num[i];
}
num[len-1] = 48 + (sum*9)%10;
break;
case MasterCard:
num[0] = 5+48;
num[1] = 48 + ((rand()%5)+1);
for(int i=2;i<len-1;i++){
num[i] = 48 + rand()%10;
}
for(int i=len-3;i>=2;i=i-2){
int n = (num[i]-'0') * 2;
if(n>9){
n = (n/10) + (n%10);
}
num[i] = n + 48;
}
for(int i=0;i<len-1;i++){
sum += num[i];
}
num[len-1] = 48 + (sum*9)%10;
break;
case Discover:
num[0] = 6+48;
num[1] = 48;
num[2] = 1+48;
num[3] = 1+48;
for(int i=4;i<len-1;i++){
num[i] = 48 + rand()%10;
}
for(int i=len-3;i>=4;i=i-2){
int n = (num[i]-'0') * 2;
if(n>9){
n = (n/10) + (n%10);
}
num[i] = n + 48;
}
for(int i=0;i<len-1;i++){
sum += num[i];
}
num[len-1] = 48 + (sum*9)%10;   
break;
}

return num;
}
void flipDig(char card[]){

}
bool validCC(char cardNo[]){
int sum = 0;
for(int i=15;i>=0;i--){
sum+=(cardNo[i]-'0');
}

return (sum % 10 == 0);
}
int main(){
srand(time(0));   
int val=0, inv=0;   
for(int i=1; i<10000;i=i+4){
int j=0;
for(int card = AmericanExpress; card <= Discover; card++){
char *a = genCC(CrdCard(card));
cout<<i+j<<". Card No: "<<a<<" Valid: ";
if(validCC(a)){
cout<<"Yes\n";
val++;
}else{
cout<<"No\n";
inv++;
}
j++;
}
}
cout<<"Total valid cards: "<<val<<endl;   
cout<<"Total invalid cards: "<<inv<<endl;   
return 0;
}

OUTPUT