TIL 20230227

이번 주 목표

JAVA 완강

오늘 목표

JAVA 3주차

JAVA 4주차

JAVA 5주차

오늘 한 것

JAVA 3주차

JAVA 4주차

JAVA 5주차

오늘 스케줄

AM 9:00 JAVA 공부

PM 10:00 TIL 작성

PM 11:00 취침

1. 3주차 숙제 : 추상화를 이용해 계산기 만들기

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.println("첫 번째 숫자를 입력하세요.");
        int firstNumber = sc.nextInt();

        System.out.println("두 번째 숫자를 입력하세요.");
        int secondNumber = sc.nextInt();

        System.out.println("연산자를 입력하세요.");
        String operation = sc.next();
        Calculator calculator = new Calculator(new AddOperation());

        switch (operation){
            case "+":
                calculator.operation = new AddOperation();
                System.out.println(calculator.calculate(firstNumber,secondNumber));
                break;
            case "-":
                calculator.operation = new SubstractOperation();
                System.out.println(calculator.calculate(firstNumber,secondNumber));
                break;
            case "*":
                calculator.operation = new MultiplyOperation();
                System.out.println(calculator.calculate(firstNumber,secondNumber));
                break;
            case "/":
                calculator.operation = new DivideOperation();
                System.out.println(calculator.calculate(firstNumber,secondNumber));
                break;
            case "%":
                System.out.println(firstNumber % secondNumber);
                break;
        }
    }
}

class Calculator {
    AbstractOperation operation ;

    Calculator (AbstractOperation operation){
        this.operation = operation;
    }
 double calculate (int firstNumber, int secondNumber){
        double answer = 0.0;
        answer = operation.operate(firstNumber,secondNumber);
        return answer;
 }

 void setOperation (String opeoperationrator){
     this.operation = operation;
 }
}

abstract  class AbstractOperation{
    AbstractOperation () {
      String operator;
    }
    abstract double operate(int firstNumber, int secondNumber);
}

class AddOperation extends  AbstractOperation{

    double operate(int firstNumber, int secondNumber){
        return firstNumber + secondNumber;
    }
}

class SubstractOperation extends  AbstractOperation{
  @Override
    double operate(int firstNumber, int secondNumber){
        return firstNumber - secondNumber;
    }
}

class MultiplyOperation extends  AbstractOperation{
    @Override
    double operate(int firstNumber, int secondNumber){
        return firstNumber * secondNumber;
    }
}

class DivideOperation extends  AbstractOperation{
    @Override
    double operate(int firstNumber, int secondNumber){
        return firstNumber / secondNumber;
    }
}

 

2. 4주차 숙제 : 예외처리 한 계산기 만들기

import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
    public static void main(String[] args) throws Exception {
        boolean calculateEnded = false;
        // 구현 2.
        CalculatorApp calculatorApp = new CalculatorApp();
        calculatorApp.start();
    }
}

class Calculator {
    private int firstNumber;
    private int secondNumber;

    private AbstractOperation operation;

    public Calculator(AbstractOperation operation) {
        this.operation = operation;
    }

    public Calculator() {
    }

    public void setOperation(AbstractOperation operation) {
        this.operation = operation;
    }

    public void setFirstNumber(int firstNumber) {
        this.firstNumber = firstNumber;
    }

    public void setSecondNumber(int secondNumber) {
        this.secondNumber = secondNumber;
    }

    public double calculate() {
        double answer = 0;
        answer = operation.operate(this.firstNumber, this.secondNumber);
        return answer;
    }

}

class BadInputException extends Exception {
    public BadInputException(String type) {
        super("잘못된 입력입니다! " + type + "을 입력해주세요!");
    }
}


 class Parser {
   static final String OPERATION_REG = "[+\\-*/]";
    static final String NUMBER_REG = "^[0-9]*$";
    Pattern numberPattern  = Pattern.compile(NUMBER_REG);
    Pattern operationPattern = Pattern.compile(OPERATION_REG);

     final Calculator calculator = new Calculator();


     Parser parseFirstNum(String firstInput) throws BadInputException {
        // 구현 1.
       Matcher matcher = numberPattern.matcher(firstInput);
       boolean isMatch = matcher.matches();
       if (isMatch == false){
           throw new BadInputException(firstInput);
       } else {
        this.calculator.setFirstNumber(Integer.valueOf(firstInput));
        return this;
       }
    }

     Parser parseSecondNum(String secondInput) throws BadInputException {
        // 구현 1.
         Matcher matcher = numberPattern.matcher(secondInput);
         boolean isMatch = matcher.matches();
         if (isMatch == false){
             throw new BadInputException(secondInput);
         } else{
             this.calculator.setSecondNumber(Integer.valueOf(secondInput));
             return this;
         }
    }

    Parser parseOperator(String operationInput) throws BadInputException {
        // 구현 1.
        Matcher matcher = operationPattern.matcher(operationInput);
        boolean isMatch = matcher.matches();
        if (isMatch == false){
            throw new BadInputException(operationInput);
        } else{
           switch (operationInput){
               case "+":
                   this.calculator.setOperation(new AddOperation());
                   break;
               case "-":
                   this.calculator.setOperation(new SubstractOperation());
                   break;
               case "*":
                   this.calculator.setOperation(new MultiplyOperation());
                   break;
               case "/":
                   this.calculator.setOperation(new DivideOperation());
                   break;
           }
            return this;
        }
    }

    double executeCalculator() {
        return calculator.calculate();
    }
}



class CalculatorApp {

    public static boolean start() throws Exception{
        Parser parser = new Parser();
        Scanner scanner = new Scanner(System.in);

        System.out.println("첫번째 숫자를 입력해주세요!");
        String firstInput = scanner.nextLine();
        parser.parseFirstNum(firstInput);

        System.out.println("연산자를 입력해주세요!");
        String operator = scanner.nextLine();
        parser.parseOperator(operator);

        System.out.println("두번째 숫자를 입력해주세요!");
        String secondInput = scanner.nextLine();
        parser.parseSecondNum(secondInput);

        System.out.println("연산 결과 : " + parser.executeCalculator());
        return true;
    }


}

abstract class AbstractOperation {
    public abstract double operate(int firstNumber, int secondNumber);
}

 class AddOperation extends AbstractOperation{
    @Override
    public double operate(int firstNumber, int secondNumber){
        return firstNumber + secondNumber;
    }
}

 class SubstractOperation extends AbstractOperation{
    @Override
    public double operate(int firstNumber, int secondNumber){
        return firstNumber - secondNumber;
    }
}

class MultiplyOperation extends AbstractOperation{
    @Override
    public double operate(int firstNumber, int secondNumber){
        return firstNumber * secondNumber;
    }
}
class DivideOperation extends AbstractOperation{
    @Override
    public double operate(int firstNumber, int secondNumber){
        return firstNumber / secondNumber;
    }
}

 

3. 5주차 숙제 Stream 이용하기

---

정리 

자바를 빠르게 흝었다. 내일은 스프링 강의 듣고 열심히 또 해봐야겠다.

 

 

KPT

Keep

열심히 하려고는 하는 것

Problem

조금 더 열심히 집중 못하는 것

Try

주어진 시간에 최선을 다하자.

소감

내 집중력에 내가 실망했다. 

가끔 딴짓에 심취해서 몇 시간이 흐르는데 이런 시간을 줄여야겠다.

강의에 집중을 못해서 그나마 중요한 개념을 강의자료로 흝고 숙제 위주로 훅훅 지나쳤는데

스프링 강의를 다 듣고 나면 다시 살펴봐야겠다.