class Student{
    private:
        int age;
        string first_name;
        string last_name;
        int standard;
    public:
        
        int get_age(){
            return this->age;
        }
        void set_age(int age){
            this->age = age;
        }
        
        string get_first_name(){
            return this->first_name;
        }

        void set_first_name(string first_name){
            this->first_name = first_name;
        }
        string get_last_name(){
            return this->last_name;
        }
        void set_last_name(string last_name){
            this->last_name = last_name;
        }
        
        int get_standard(){
            return this->standard;
        }
        void set_standard(int standard){
            this->standard = standard;
        }
        
        string to_string(){
            return std::to_string(this->age) + "," + this->first_name + "," + this->last_name + "," + std::to_string(this->standard); 
        }    
};