Changes made to branch from main

Author: shahriar573

Calculator.java

@@ -0,0 +1,25 @@
+public class Computer
+{
+    public int add(int a, int b)
+    {
+        return a+b;
+    }
+
+    public int subtract(int a, int b)
+    {
+        return a-b;
+    }
+
+    public int multiply(int a, int b)
+    {
+        return a*b;
+    }
+
+    public int divide(int a, int b)
+    {
+        if (b == 0) {
+            throw new ArithmeticException("Division by zero is not allowed.");
+        }
+        return a/b;
+    }
+}