Add Calculator class with basic arithmetic methods

Author: Adi-Sin101

src/Features/Calculator.java

@@ -0,0 +1,21 @@
+public class Calculator {
+
+    public double add(double a, double b) {
+        return a + b;
+    }
+
+    public double subtract(double a, double b) {
+        return a - b;
+    }
+
+    public double multiply(double a, double b) {
+        return a * b;
+    }
+
+    public double divide(double a, double b) {
+        if (b == 0.0) {
+            throw new IllegalArgumentException("Division by zero");
+        }
+        return a / b;
+    }
+}