[4기 - 김재웅] 1~2주차 과제 : 계산기 구현 미션 제출합니다.

calculator/src/main/java/org/example/CalOrder.java

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+package org.example;
+
+public interface CalOrder {
+    public abstract void calPriorityFirst();
+    public abstract void calPrioritySecond();
+}

calculator/src/main/java/org/example/Calculate.java

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+package org.example;
+
+import java.util.Stack;
+
+public class Calculate implements CalOrder{
+    private String expression;
+    Stack<String> expressionStack = new Stack<>();
+    ExpressionRepository repository = new ExpressionRepository();
+    int result = 0;
+
+    public Calculate(String expression) {
+        this.expression = expression;
+        String[] expressionArr = expression.split(" ");
+        for (String inputVal : expressionArr) {
+            expressionStack.add(inputVal);
+        }
+    }
+
+    public void calculate(){
+        calPriorityFirst();
+        calPrioritySecond();
+    }
+
+    @Override
+    public void calPriorityFirst() {
+        for (int i = 1; i < expressionStack.size(); i+=2) {
+            if (expressionStack.get(i).equals("*")) {
+                multiply(i);
+                i -= 2;
+            } else if (expressionStack.get(i).equals("/")) {
+                divide(i);
+                i -= 2;
+            }
+        }
+    }
+
+    @Override
+    public void calPrioritySecond() {
+        result = Integer.parseInt(expressionStack.get(0));
+        for (int i = 1; i < expressionStack.size(); i += 2) {
+            if (expressionStack.get(i).equals("+")) {
+                result += Integer.parseInt(expressionStack.get(i + 1));
+            } else {
+                result -= Integer.parseInt(expressionStack.get(i + 1));
+            }
+        }
+        System.out.println(result);
+        repository.save(expression,result);
+    }
+
+    public void multiply(int idx){
+        result = Integer.parseInt(expressionStack.get(idx - 1)) * Integer.parseInt(expressionStack.get(idx + 1));
+        expressionStack.add(idx - 1, String.valueOf(result));
+        expressionStack.remove(idx);
+        expressionStack.remove(idx);
+        expressionStack.remove(idx);
+    }
+
+    public void divide(int idx) {
+        result = Integer.parseInt(expressionStack.get(idx - 1)) / Integer.parseInt(expressionStack.get(idx + 1));
+        expressionStack.add(idx - 1, String.valueOf(result));
+        expressionStack.remove(idx);
+        expressionStack.remove(idx);
+        expressionStack.remove(idx);
+    }
+}

calculator/src/main/java/org/example/ExpressionRepository.java

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+package org.example;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ExpressionRepository implements Repository {
+    private static List<String> store = new ArrayList<>();
+
+    @Override
+    public void save(String expression, int result) {
+        store.add(expression + " = " + result);
+    }
+
+    @Override
+    public List<String> getRecord() {
+        return store;
+    }
+}

calculator/src/main/java/org/example/Main.java

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+package org.example;
+
+import java.util.List;
+import java.util.Scanner;
+
+public class Main {
+    public static void main(String[] args) {
+
+        int choice = 0;
+
+        while (true) {
+            choice = getChoice();
+            System.out.println();
+            if (choice == 1) {
+                new UserInterfaceImpl().showRecord();
+            } else {
+                String expression = typeExpression();
+                new Calculate(expression).calculate();
+            }
+            System.out.println();
+        }
+    }
+
+    public static int getChoice() {
+        Scanner scanner = new Scanner(System.in);
+
+        System.out.println("1. 조회\n2. 계산\n");
+        System.out.print("선택 : ");
+        return scanner.nextInt();
+    }
+
+    public static String typeExpression() {
+        Scanner scanner = new Scanner(System.in);
+        return scanner.nextLine();
+    }
+}

calculator/src/main/java/org/example/Repository.java

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+package org.example;
+
+import java.util.List;
+
+public interface Repository {
+    void save(String expression, int result);
+    List<String> getRecord();
+}

calculator/src/main/java/org/example/UserInterface.java

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+package org.example;
+
+public interface UserInterface {
+    public abstract void showRecord();
+}

calculator/src/main/java/org/example/UserInterfaceImpl.java

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+package org.example;
+
+import java.util.List;
+
+public class UserInterfaceImpl implements UserInterface{
+
+    ExpressionRepository repository = new ExpressionRepository();
+    @Override
+    public void showRecord() {
+        List<String> record = repository.getRecord();
+        record.forEach(System.out::println);
+    }
+}