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

.gitattributes

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+#
+# https://help.github.com/articles/dealing-with-line-endings/
+#
+# Linux start script should use lf
+/gradlew        text eol=lf
+
+# These are Windows script files and should use crlf
+*.bat           text eol=crlf
+

.gitignore

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+# Compiled class files
+*.class
+
+# Log files
+*.log
+
+# IntelliJ IDEA files
+.idea/
+
+# Eclipse files
+.classpath
+.project
+.settings/
+
+# Build output
+build/
+out/
+
+# Dependency directories
+.lib/
+libs/
+
+# Gradle specific
+.gradle/
+gradle/

app/build.gradle

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+/*
+ * This file was generated by the Gradle 'init' task.
+ *
+ * This generated file contains a sample Java application project to get you started.
+ * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
+ * User Manual available at https://docs.gradle.org/8.1.1/userguide/building_java_projects.html
+ */
+
+plugins {
+    // Apply the application plugin to add support for building a CLI application in Java.
+    id 'application'
+}
+
+repositories {
+    // Use Maven Central for resolving dependencies.
+    mavenCentral()
+}
+
+dependencies {
+    // Use JUnit Jupiter for testing.
+    testImplementation 'org.junit.jupiter:junit-jupiter:5.9.1'
+
+    // This dependency is used by the application.
+    implementation 'com.google.guava:guava:31.1-jre'
+    testImplementation 'org.assertj:assertj-core:3.21.0'
+    // JUnit 5
+    testImplementation 'org.junit.jupiter:junit-jupiter:5.7.2'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.2'
+}
+
+// Apply a specific Java toolchain to ease working on different environments.
+java {
+    toolchain {
+        languageVersion = JavaLanguageVersion.of(11)
+    }
+}
+
+application {
+    // Define the main class for the application.
+    mainClass = 'java.calculator.App'
+}
+
+tasks.named('test') {
+    // Use JUnit Platform for unit tests.
+    useJUnitPlatform()
+}

app/src/main/java/example/Main.java

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+package example;
+
+import example.calculator.CalculatorController;
+import example.calculator.model.Calculator;
+import example.calculator.view.Input;
+import example.calculator.view.Output;
+
+public class Main {
+    public static void main(String[] args) {
+        CalculatorController calculatorController = new CalculatorController(new Input(), new Output(),
+                new Calculator());
+        calculatorController.start();
+    }
+}

app/src/main/java/example/calculator/CalculatorController.java

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+package example.calculator;
+
+import example.calculator.model.Calculator;
+import example.calculator.view.Output;
+import example.calculator.view.Input;
+
+public class CalculatorController {
+    private Input input;
+    private Output output;
+    private Calculator calculator;
+
+    public CalculatorController(Input input, Output output, Calculator calculator) {
+        this.input = input;
+        this.output = output;
+        this.calculator = calculator;
+    }
+
+    public void start() {
+        while (true) {
+            output.printMenu();
+            int choice = input.getIntInput();
+
+            switch (choice) {
+                case 1:
+                    output.printCalculationHistory(calculator.getCalculationHistory());
+                    break;
+                case 2:
+                    handleCalculation();
+                    break;
+                default:
+                    System.out.println("잘못된 선택입니다. 다시 선택해주세요.");
+            }
+        }
+    }
+
+    private void handleCalculation() {
+        input.getStringInput();
+
+        System.out.print("수식을 입력하세요: ");
+        String expression = input.getStringInput();
+
+        String[] tokens = expression.split("\\s+");
+        double result = calculator.handleCalculation(tokens, expression);
+
+        output.printResult(result);
+    }
+}

app/src/main/java/example/calculator/model/Calculator.java

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+package example.calculator.model;
+
+import example.calculator.model.operation.Addition;
+import example.calculator.model.operation.CalculationOperation;
+import example.calculator.model.operation.Division;
+import example.calculator.model.operation.Multiplication;
+import example.calculator.model.operation.Subtraction;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class Calculator {
+    private Map<String, CalculationOperation> calculationOperations;
+    private List<String> calculationHistory;
+
+    public Calculator() {
+        calculationOperations = new HashMap<>();
+        calculationOperations.put("*", new Multiplication());
+        calculationOperations.put("/", new Division());
+        calculationOperations.put("+", new Addition());
+        calculationOperations.put("-", new Subtraction());
+
+        calculationHistory = new ArrayList<>();
+    }
+
+    public List<String> getCalculationHistory() {
+        return calculationHistory;
+    }
+
+    public double calculate(double a, double b, String operator) {
+        CalculationOperation operation = calculationOperations.get(operator);
+        if (operation == null) {
+            throw new IllegalArgumentException("Invalid operator: " + operator);
+        }
+
+        return operation.calculate(a, b);
+    }
+
+    private void addToCalculationHistory(String expression) {
+        calculationHistory.add(expression);
+    }
+
+    public double handleCalculation(String[] tokens, String expression) {
+        List<String> operators = new ArrayList<>();
+        List<Double> operands = new ArrayList<>();
+
+        for (String token : tokens) {
+            if (token.matches("[+\\-*/]")) {
+                operators.add(token);
+            } else {
+                operands.add(Double.parseDouble(token));
+            }
+        }
+
+        double result = getResult(operators, operands);
+
+        String calculationExpression = expression.replaceAll("\\s+", "");
+        addToCalculationHistory(calculationExpression + " = " + result);
+        return result;
+    }
+
+    private double getResult(List<String> operators, List<Double> operands) {
+        calculateOperations(operands, operators, "*", "/");
+        calculateOperations(operands, operators, "+", "-");
+
+        return operands.get(0);
+    }
+
+    private void calculateOperations(List<Double> operands, List<String> operators, String... targetOperators) {
+        for (String targetOperator : targetOperators) {
+            for (int i = 0; i < operators.size(); i++) {
+                String operator = operators.get(i);
+                if (operator.equals(targetOperator)) {
+                    double operand1 = operands.get(i);
+                    double operand2 = operands.get(i + 1);
+                    double result = calculate(operand1, operand2, operator);
+
+                    operands.set(i, result);
+                    operands.remove(i + 1);
+                    operators.remove(i);
+                    i--;
+                }
+            }
+        }
+    }
+}

app/src/main/java/example/calculator/model/Menu.java

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+package example.calculator.model;
+
+public enum Menu {
+    조회(1),
+    계산(2);
+
+    private final int value;
+
+    Menu(int value) {
+        this.value = value;
+    }
+
+    public int getValue() {
+        return value;
+    }
+}

app/src/main/java/example/calculator/model/operation/Addition.java

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+package example.calculator.model.operation;
+
+public class Addition implements CalculationOperation {
+    @Override
+    public double calculate(double a, double b) {
+        return a + b;
+    }
+
+    @Override
+    public String getOperator() {
+        return "+";
+    }
+}

app/src/main/java/example/calculator/model/operation/CalculationOperation.java

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+package example.calculator.model.operation;
+
+public interface CalculationOperation {
+    double calculate(double a, double b);
+
+    String getOperator();
+}

app/src/main/java/example/calculator/model/operation/Division.java

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+package example.calculator.model.operation;
+
+public class Division implements CalculationOperation {
+    @Override
+    public double calculate(double a, double b) {
+        if (b != 0) {
+            return a / b;
+        } else {
+            throw new IllegalArgumentException("Cannot divide by zero.");
+        }
+    }
+
+    @Override
+    public String getOperator() {
+        return "/";
+    }
+}

app/src/main/java/example/calculator/model/operation/Multiplication.java

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+package example.calculator.model.operation;
+
+public class Multiplication implements CalculationOperation {
+    @Override
+    public double calculate(double a, double b) {
+        return a * b;
+    }
+
+    @Override
+    public String getOperator() {
+        return "*";
+    }
+}

app/src/main/java/example/calculator/model/operation/Subtraction.java

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+package example.calculator.model.operation;
+
+public class Subtraction implements CalculationOperation {
+    @Override
+    public double calculate(double a, double b) {
+        return a - b;
+    }
+
+    @Override
+    public String getOperator() {
+        return "-";
+    }
+}

app/src/main/java/example/calculator/view/Input.java

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+package example.calculator.view;
+
+import java.util.Scanner;
+
+public class Input {
+    private Scanner scanner;
+
+    public Input() {
+        scanner = new Scanner(System.in);
+    }
+
+    public int getIntInput() {
+        return scanner.nextInt();
+    }
+
+    public String getStringInput() {
+        return scanner.nextLine();
+    }
+}

app/src/main/java/example/calculator/view/Output.java

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+package example.calculator.view;
+
+import example.calculator.model.Menu;
+import java.util.List;
+
+public class Output {
+    public void printCalculationHistory(List<String> calculationHistory) {
+        for (String history : calculationHistory) {
+            System.out.println(history);
+        }
+    }
+
+    public void printMenu() {
+        System.out.println(Menu.조회.getValue() + ". " + Menu.조회);
+        System.out.println(Menu.계산.getValue() + ". " + Menu.계산);
+    }
+
+    public void printResult(double result) {
+        System.out.println("결과: " + result);
+    }
+}

app/src/test/java/example/calculator/model/CalculatorTest.java

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+package example.calculator.model;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+public class CalculatorTest {
+
+    @ParameterizedTest
+    @MethodSource("testData")
+    public void testCalculate(double operand1, double operand2, String operator, double expected) {
+        Calculator calculator = new Calculator();
+        double result = calculator.calculate(operand1, operand2, operator);
+        assertThat(result).isEqualTo(expected);
+    }
+
+    private static Stream<Arguments> testData() {
+        return Stream.of(
+                Arguments.of(1, 2, "+", 3),
+                Arguments.of(1, 2, "-", -1),
+                Arguments.of(2, 3, "*", 6),
+                Arguments.of(4, 2, "/", 2)
+        );
+    }
+}