HackerRank C++ Class

ou have to create a class, named Student, representing the student's details, as mentioned above, and store the data of a student. Create setter and getter functions for each element; that is, the class should at least have following functions:

get_age, set_age
get_first_name, set_first_name
get_last_name, set_last_name
get_standard, set_standard
Also, you have to create another method to_string() which returns the string consisting of the above elements, separated by a comma(,). You can refer to stringstream for this.

#include <iostream>
using namespace std;
class Student
{
     int age, standard;
    string first_name, last_name;
    public:
        void set_age(int age)
        {
            this->age=age;
        }
        void set_standard(int standard)
        {
            this->standard=standard;
        
        }
        void set_first_name(string fname)
        {
            first_name=fname;

        }
         void set_last_name(string lname)
        {
            last_name=lname;   
        }
         int get_age()
         {
             return age;
         }

 int get_standard()
        {
            return standard;
        
        }
        string get_first_name()
        {
            return(first_name);

        }
        string get_last_name()
        {
            return(last_name);

        }
        void to_string(){
            cout<<age<<","<<first_name<<","<<last_name<<","<<standard;
        }
};
    int main() {
    int age, standard;
    string first_name, last_name;
    
    cin >> age >> first_name >> last_name >> standard;
    
    Student st;
    st.set_age(age);
    st.set_standard(standard);
    st.set_first_name(first_name);
    st.set_last_name(last_name);
    
    cout << st.get_age() << "\n";
    cout << st.get_last_name() << ", " << st.get_first_name() << "\n";
    cout << st.get_standard() << "\n";
    cout << "\n";
     st.to_string();
    
    return 0;
}