인프런 커뮤니티 질문&답변

package method.ex;

import java.util.Scanner;

public class MethodEx4 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int balance = 0;

        while (true) {
            printMenu();
            int option = getMenuOption(scanner);
            
            balance = processOption(option, balance, scanner);

            if (option == 4) {
                break;
            }
        }
    }

    public static int getMenuOption(Scanner scanner) {
        System.out.print("선택: ");
        return scanner.nextInt();
    }

    public static int processOption(int option, int balance, Scanner scanner) {
        if (option == 1) {
            return deposit(balance, scanner);
        } else if (option == 2) {
            return withdraw(balance, scanner);
        } else if (option == 3) {
            showBalance(balance);
        } else if (option == 4) {
            printFinish();
        } else {
            printError();
        }
        return balance;
    }

    public static void printMenu() {
        System.out.println("---------------------------------");
        System.out.println("1.입금 | 2.출금 | 3.잔액 확인 | 4.종료");
        System.out.println("---------------------------------");
    }

    public static void printFinish() {
        System.out.println("시스템을 종료합니다.");
    }

    public static void printError() {
        System.out.println("올바른 선택이 아닙니다. 다시 선택해주세요.");
    }

    public static int deposit(int balance, Scanner scanner) {
        System.out.print("입금액을 입력하세요: ");
        int deposit = scanner.nextInt();
        balance += deposit;
        System.out.println(deposit + "원을 입금하였습니다. 현재 잔액: " + balance);
        return balance;
    }

    public static int withdraw(int balance, Scanner scanner) {
        System.out.print("출금액을 입력하세요: ");
        int withdraw = scanner.nextInt();

        if (balance >= withdraw) {
            balance -= withdraw;
            System.out.println(withdraw + "원을 출금하였습니다. 현재 잔액: " + balance);
        } else {
            System.out.println(withdraw + "원을 출금하려 했으나 잔액이 부족합니다.");
        }
        return balance;
    }

    public static void showBalance(int balance) {
        System.out.println("현재 잔액: " + balance + "원");
    }
}