#include <iostream>

using namespace std;

void show_main_menu(){
	cout<< "성적관리시스템에 오신걸 환영합니다.!"<<endl;
	cout<< "메뉴 번호를 선택하세요 "<<endl;
	cout<< "1)과목추가" <<endl;
	cout<< "2)성적추가" <<endl;
	cout<< "3)성적출력" <<endl;
	cout<< "0)종료" <<endl;
}

void do_option(int option){

	cout<<"선택하신 번호를 입력하세요 : ";
	cin>> option;

	switch(option){
		case 1:
			cout << "add_subject" <<endl;
			break;
		case 2:
			cout << "add_grade" <<endl;
			break;
		case 3:
			cout << "print_report" <<endl;
			break;
		default :
	     	break;
	}
}

void main()
{
	int option=0;
	do{
		show_main_menu();
		do_option(option);

	}while(option != 0);
}