Add cpplint to validate_filenames (#643)

* Add cpplint to validate_filenames

* Update and rename Happy_number.cpp to happy_number.cpp

* Update validate_new_filenames.yml

* pip install cpplint

* python3 -m pip install cpplint

* python3 -m pip install --useer cpplint

* python3 -m pip install --user cpplint

* Update validate_new_filenames.yml

* sudo python3 -m pip install cpplint

* sudo python3 -m pip install cpplint

* uses: actions/setup-python@v1

* Run cpplint first

* cpp_exts

* tuple

* cpplint_modified_files

Others/happy_number.cpp

@@ -1,19 +1,18 @@
 /* A happy number is a number whose sum of digits is calculated until the sum is a single digit,
   and this sum turns out to be 1 */
-#include <iostream>
-using namespace std;
 
-int main()
-{
+// Copyright 2019 TheAlgorithms contributors
+
+#include <iostream>
+
+int main() {
   int n, k, s = 0, d;
-  cout << "Enter a number:";
-  cin >> n;
+  std::cout << "Enter a number:";
+  std::cin >> n;
   s = 0;
   k = n;
-  while (k > 9)
-  {
-    while (k != 0)
-    {
+  while (k > 9) {
+    while (k != 0) {
       d = k % 10;
       s += d;
       k /= 10;
@@ -22,8 +21,8 @@ int main()
     s = 0;
   }
   if (k == 1)
-    cout << n << " is a happy number" << endl;
+    std::cout << n << " is a happy number" << std::endl;
   else
-    cout << n << " is not a happy number" << endl;
+    std::cout << n << " is not a happy number" << std::endl;
   return 0;
 }