Adding factorial code in C++

C++/factorial.cpp

@@ -0,0 +1,22 @@
+//  Created by Riya Pannu on 15/10/17.
+
+#include<iostream>
+using namespace std;
+
+long long int factorial(long long int n) {
+    if (n == 0)
+        return 1;
+    else
+        return n * factorial(n-1);
+
+}
+
+int main() {
+    long long int n;
+    cout<<"Enter a number \n";
+    cin >> n;
+
+    long long int result = factorial(n);
+    cout << "The factorial of "<<n<<" is "<<result << endl;
+    return 0;
+}