(이주연) StringCalculator 리뷰 요청드립니다.

src/main/java/Calculator.java

@@ -0,0 +1,33 @@
+public class Calculator {
+    public double calculate(String expression) {
+        String[] tokens = expression.split(" ");
+        double currentResult = Double.parseDouble(tokens[0]);
+
+        for (int i = 1; i < tokens.length; i += 2) {
+            String operator = tokens[i];
+            double number = Double.parseDouble(tokens[i + 1]);
+
+            switch (operator) {
+                case "+":
+                    currentResult += number;
+                    break;
+                case "-":
+                    currentResult -= number;
+                    break;
+                case "*":
+                    currentResult *= number;
+                    break;
+                case "/":
+                    if (number == 0) {
+                        throw new ArithmeticException("0으로 나눌 수 없습니다.");
+                    }
+                    currentResult /= number;
+                    break;
+                default:
+                    System.out.println("지원하지 않는 연산자입니다: " + operator);
+                    return 0;
+            }
+        }
+        return currentResult;
+    }
+}

src/main/java/Main.java

@@ -1,5 +1,22 @@
+import java.util.Scanner;
+
 public class Main {
     public static void main(String[] args) {
-        System.out.println("1 + 1 = 2");
+        Scanner scanner = new Scanner(System.in);
+        System.out.println("계산할 수식을 입력하세요 (예: 30 + 20 / 2 * 4):");
+        String expression = scanner.nextLine();
+
+        Validator validator = new Validator();
+        if (validator.isValid(expression)) {
+            Calculator calculator = new Calculator();
+            try {
+                double result = calculator.calculate(expression);
+                System.out.println("결과: " + result);
+            } catch (ArithmeticException e) {
+                System.out.println("계산 중 오류가 발생했습니다: " + e.getMessage());
+            }
+        } else {
+            System.out.println("잘못된 수식 형식입니다. 다시 입력해주세요.");
+        }
     }
 }

src/main/java/Validator.java

@@ -0,0 +1,34 @@
+public class Validator {
+    public boolean isValid(String expression) {
+        String[] tokens = expression.split(" ");
+
+        if (tokens.length % 2 == 0) {
+            return false;
+        }
+
+        if (!isNumeric(tokens[0])) {
+            return false;
+        }
+
+        for (int i = 1; i < tokens.length; i += 2) {
+            if (!isOperator(tokens[i]) || !isNumeric(tokens[i + 1])) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    private boolean isNumeric(String str) {
+        try {
+            Double.parseDouble(str);
+            return true;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+
+    private boolean isOperator(String str) {
+        return str.equals("+") || str.equals("-") || str.equals("*") || str.equals("/");
+    }
+}