Validate if there are more or less than the allowed rolls, if the numbers are valid and if the number isn't a number.

include/FileUtil.h

@@ -0,0 +1,19 @@
+#ifndef FILEUTIL_H
+#define FILEUTIL_H
+
+#include <string>
+#include <vector>
+
+using namespace std;
+
+class FileUtil {
+    public:
+        FileUtil() = default;
+        
+        ~FileUtil() = default;
+        
+        static string getFile(char *path);
+        static bool fileExists(char *path);
+};
+
+#endif

include/NumberHelper.h

@@ -18,9 +18,10 @@ class NumberHelper {
         static vector<Frame> createFrames(vector<int> rolls);
     
     private:
-        static Frame CreateStrikeFrame(int i);
-        static Frame CreateFreeFrame(int i, int j);
-        static Frame CreateBonusFrame(int i, int j, int k);
+        static Frame createStrikeFrame(int i);
+        static Frame createFreeFrame(int i, int j);
+        static Frame createBonusFrame(int i, int j, int k);
+        static bool isNumber(const std::string& str);
 };