how to change the if statement in the main into the private member function!

help me explain it clear

//Class with Private Members //Program to demonstrate the class DayOfYear. #include using namespace std; class DayOfYear public: void input(); void output(); void set(int newMonth, int new Day); //Mutator functions to set or change the values of objects int get Month(); //Accessor function: Returns the month, 1 for January, 2 for February, etc. int getDay(); //Accessor function: Returns the day of the month. private: void checkDate(); int month; int day; int main() DayOfYear today, Batman Birthday: cout > month; cout > day; checkDate(); void DayOfYear::output) cout 12) 11 (day 31)) cout