From 408aeb63984dd6a66bf62fdd1b2a8724e8dce10a Mon Sep 17 00:00:00 2001
From: bo-10000 <seot100@naver.com>
Date: Mon, 24 Mar 2025 21:12:08 +0900
Subject: [PATCH] =?UTF-8?q?feat:=20step1=20=EC=9A=94=EA=B5=AC=EC=82=AC?=
=?UTF-8?q?=ED=95=AD=20=EA=B5=AC=ED=98=84?=
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---
src/main/java/Calculator.java | 37 +++++++++++++++++++++
src/main/java/Operand.java | 42 ++++++++++++++++++++++++
src/test/java/CalculatorTest.java | 54 +++++++++++++++++++++++++++++++
3 files changed, 133 insertions(+)
create mode 100644 src/main/java/Calculator.java
create mode 100644 src/main/java/Operand.java
create mode 100644 src/test/java/CalculatorTest.java
diff --git a/src/main/java/Calculator.java b/src/main/java/Calculator.java
new file mode 100644
index 00000000000..fb245c51852
--- /dev/null
+++ b/src/main/java/Calculator.java
@@ -0,0 +1,37 @@
+public class Calculator {
+ private static void validate_input(String expression) {
+ if (expression == null || expression.isBlank()) {
+ throw new IllegalArgumentException("입력 값이 null이거나 빈 공백 문자입니다.");
+ }
+ }
+
+ private static int updateResult(int result, Operand operand, int number) {
+ if (operand == null) {
+ return number;
+ }
+ else {
+ return operand.operate(result, number);
+ }
+ }
+
+ public static int run(String expression) {
+ validate_input(expression);
+
+ int result = 0;
+ Operand operand = null;
+
+ String[] tokens = expression.split(" ");
+ for (int i = 0; i < tokens.length; i++) {
+ String t = tokens[i];
+ if (i % 2 == 0) {
+ int number = Integer.parseInt(t);
+ result = updateResult(result, operand, number);
+ }
+ else {
+ operand = new Operand(t);
+ }
+ }
+
+ return result;
+ }
+}
diff --git a/src/main/java/Operand.java b/src/main/java/Operand.java
new file mode 100644
index 00000000000..6f826053f2b
--- /dev/null
+++ b/src/main/java/Operand.java
@@ -0,0 +1,42 @@
+class Operand {
+ private final String VALUE;
+
+ Operand(String value) {
+ this.VALUE = value;
+ }
+
+ private int sum(int num1, int num2) {
+ return num1 + num2;
+ }
+
+ private int subtract(int num1, int num2) {
+ return num1 - num2;
+ }
+
+ private int multiply(int num1, int num2) {
+ return num1 * num2;
+ }
+
+ private int divide(int num1, int num2) {
+ return num1 / num2;
+ }
+
+ int operate(int num1, int num2) {
+ if (VALUE.equals("+")) {
+ return sum(num1, num2);
+ }
+ else if (VALUE.equals("-")) {
+ return subtract(num1, num2);
+ }
+ else if (VALUE.equals("*")) {
+ return multiply(num1, num2);
+ }
+ else if (VALUE.equals("/")) {
+ return divide(num1, num2);
+ }
+ else {
+ throw new IllegalArgumentException("지원하지 않는 연산자입니다.");
+ }
+ }
+
+}
diff --git a/src/test/java/CalculatorTest.java b/src/test/java/CalculatorTest.java
new file mode 100644
index 00000000000..bc85237b630
--- /dev/null
+++ b/src/test/java/CalculatorTest.java
@@ -0,0 +1,54 @@
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+public class CalculatorTest {
+ @DisplayName("덧셈 테스트")
+ @Test
+ void addTest() {
+ int result = Calculator.run("2 + 3");
+ assertEquals(5, result);
+ }
+
+ @DisplayName("뺄셈 테스트")
+ @Test
+ void subtractTest() {
+ int result = Calculator.run("5 - 3");
+ assertEquals(2, result);
+ }
+
+ @DisplayName("곱셈 테스트")
+ @Test
+ void multiplyTest() {
+ int result = Calculator.run("2 * 3");
+ assertEquals(6, result);
+ }
+
+ @DisplayName("나눗셈 테스트")
+ @Test
+ void divideTest() {
+ int result = Calculator.run("6 / 3");
+ assertEquals(2, result);
+ }
+
+ @DisplayName("입력 값이 null이거나 빈 공백 문자일 경우")
+ @ParameterizedTest
+ @ValueSource(strings = {"", " "})
+ void nullOrEmptyTest() {
+ assertThatIllegalArgumentException().isThrownBy(() -> {
+ Calculator.run(null);
+ }).withMessage("입력 값이 null이거나 빈 공백 문자입니다.");
+ }
+
+ @DisplayName("지원하지 않는 연산자일 경우")
+ @Test
+ void invalidOperatorTest() {
+ assertThatIllegalArgumentException().isThrownBy(() -> {
+ Calculator.run("2 % 3");
+ }).withMessage("지원하지 않는 연산자입니다.");
+ }
+}