fix: throw ArithmeticException on divide by zero (#9)

src/main/java/com/example/util/DivideFunction.java

@@ -8,6 +8,9 @@ public class DivideFunction implements CalcFunction {
         }
         double result = input[0];
         for (int i = 1; i < input.length; i++) {
+            if (input[i] == 0) {
+                throw new ArithmeticException("Division by zero");
+            }
             result /= input[i];
         }
         return result;

src/test/java/com/example/util/DivideFunctionTest.java

@@ -3,6 +3,7 @@ package com.example.util;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 class DivideFunctionTest {
 
@@ -27,4 +28,9 @@ class DivideFunctionTest {
     void dividesNegativeValues() {
         assertEquals(-2.0, divideFunction.calc(4.0, -2.0));
     }
+
+    @Test
+    void throwsOnDivideByZero() {
+        assertThrows(ArithmeticException.class, () -> divideFunction.calc(5.0, 0.0));
+    }
 }