Feature/calculator

Calculator.java

@@ -0,0 +1,9 @@
+public class Calculator {
+    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 double divide(int a, int b) {
+        if (b == 0) throw new ArithmeticException("Divide by zero");
+        return (double) a / b;
+    }
+}

student.java

@@ -0,0 +1,17 @@
+public class Student {
+    private String name;
+    private int age;
+
+    public Student() {}
+
+    public Student(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public String getName() { return name; }
+    public void setName(String name) { this.name = name; }
+
+    public int getAge() { return age; }
+    public void setAge(int age) { this.age = age; }
+}