refactoring, expand interface

read_uses.cpp

@@ -12,6 +12,10 @@ read_uses::read_uses(std::string name)
   this->exist = file.good();
 }
 
+bool read_uses::exist_file(){
+  return this->exist;
+}
+
 std::string* read_uses::get_uses(){
   std::string *ret=nullptr;
   if(this->exist){