From 4e07118b6394231d4901c8d61f7e4807a211767d Mon Sep 17 00:00:00 2001
From: Bindasscodder <100517651+Bindasscodder@users.noreply.github.com>
Date: Mon, 3 Oct 2022 07:56:15 -0700
Subject: [PATCH] Create credit-card-validator.cpp

---
 C++/credit-card-validator.cpp | 58 +++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 C++/credit-card-validator.cpp

diff --git a/C++/credit-card-validator.cpp b/C++/credit-card-validator.cpp
new file mode 100644
index 0000000..9699b73
--- /dev/null
+++ b/C++/credit-card-validator.cpp
@@ -0,0 +1,58 @@
+#include <stdio.h>
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+bool isNumberString(const string& s) {
+    int len = s.length();
+    for (int i = 0; i < len; i++) {
+        if (s[i] < '0' || s[i] > '9')
+            return false;
+    }
+    return true;
+}
+
+int main() {
+    string ccNumber;
+    
+    cout << "This program uses the Luhn Algorigthm to validate a CC number." << endl;
+    cout << "You can enter 'exit' anytime to quit." << endl;
+    
+    while (true) {
+        
+        cout << "Please enter a CC number to validate: ";
+        cin >> ccNumber;
+        
+        if (ccNumber == "exit")
+            break;
+        
+        else if (!isNumberString(ccNumber)) {
+            cout << "Bad input! ";
+            continue;
+        }
+            
+        int len = ccNumber.length();
+        int doubleEvenSum = 0;
+            
+        for (int i = len - 2; i >= 0; i = i - 2) {
+            int dbl = ((ccNumber[i] - 48) * 2);
+            if (dbl > 9) {
+                dbl = (dbl / 10) + (dbl % 10);
+            }
+            doubleEvenSum += dbl;
+        }
+        
+        
+        for (int i = len - 1; i >= 0; i = i - 2) {
+            doubleEvenSum += (ccNumber[i] - 48);
+        }
+        
+        
+        cout << (doubleEvenSum % 10 == 0 ? "Valid!" : "Invalid!") << endl;
+        
+        continue;        
+    }
+
+    return 0;
+}