~cpp 
#include <iostream>
#include <cstring>
using namespace std;

int selection, num;

class Man{
public:
	void select(){
		selection = 0;
		while (selection < 1 || selection > num){
			cout << ">> ";
			cin >> selection;
			if (selection < 1 || selection > num)
				cout << "잘못 입력하셨습니다. n";
		}
	};
};

class CoinCounter{
public:
	int remainders, coin;
	void resetCoins(){
		remainders = 0;
	};
	void showRemainders(){
		cout << "REMAINDERS : " << remainders << endl;
	};
	void insertCoins(){
		cout << "돈을 넣으세요.n 1. 10원 n 2. 50원 n 3. 100원 n 4. 500원 n 5. 1000원 n>> ";
		cin >> coin;
		if (coin == 1)			coin = 10;
		else if (coin == 2)		coin = 50;
		else if (coin == 3)		coin = 100;
		else if (coin == 4)		coin = 500;
		else if (coin == 5)		coin = 1000;
		else coin = 0;
		remainders += coin;
		cout << coin <<"원을 넣으셨습니다. n잔액은 " << remainders << "입니다.n";
	};
	void pay(int used){
		cout << used << "원을 사용하셨습니다.n";
		remainders -= used;
	};
};

class VendingMachine{
public:
	void showMenu(){
	num = 4;
	cout << "MAIN MENU n 1. INSERT COIN n 2. BUY n 3. RETURN THE REMAINDERS n 4. EXIT n";
	};
};

class Drink{
public:
	struct drinks{
		char name[10];
		int price;
		int quantity;
	};
	drinks detail[3];
	Drink(){
		strcpy(detail[0].name, "사이다");
		strcpy(detail[1].name, "콜라");
		strcpy(detail[2].name, "2% 부족");
		detail[0].price = 500;
		detail[1].price = 400;
		detail[2].price = 600;
		for (int i = 0 ; i < 3 ; i++)
			detail[i].quantity = 10;
	};
	void showDetails(){
		num = 3;
		cout << " 상품명t 가격t 수량n";
		for (int i = 0 ; i < 3; i++)
			cout << i+1 << ". " << detail[i].name << "t"
				<< detail[i].price << "t"
				<< detail[i].quantity << endl;
	};
	int buy(int remainders){
		if (remainders >= detail[selection - 1].price && detail[selection - 1].quantity != 0){
			cout << detail[selection - 1].name << "을 선택하셨습니다.n";
			detail[selection - 1].quantity--;
			return detail[selection - 1].price;
		}
		else if (detail[selection - 1].price > remainders)
			cout << "잔액이 부족합니다.n";
		else if (detail[selection - 1].quantity == 0)
			cout << "매진되었습니다. 다른 상품을 골라주십시오.n";
		return 0;
	};
};

int main(){
	Man man;
	CoinCounter coin_counter;
	VendingMachine vending_machine;
	Drink drink;
	int usedmoney;
	coin_counter.resetCoins();
	while(selection != 4)
	{
		vending_machine.showMenu();
		coin_counter.showRemainders();
		man.select();
		if (selection == 1)
			coin_counter.insertCoins();
		else if (selection == 2){
			drink.showDetails();
			man.select();
			usedmoney = drink.buy(coin_counter.remainders);
			coin_counter.pay(usedmoney);
		}
		else if (selection == 3){
			cout << "잔액을 반환합니다.n";
			coin_counter.resetCoins();
		}
		else if (selection == 4)
			break;
		else cout << "잘못 입력하셨습니다.n";
		system("pause");
		system("cls");
	};
	return 0;
}