Add Calculator class with basic operations

Calculator.java

@@ -0,0 +1,20 @@
+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 IllegalArgumentException("Division by zero is not allowed.b can't be zero.");
+        }
+        return (double) a / b;
+    }   
+}

Student.java

@@ -0,0 +1,21 @@
+public class Student{
+    private String name;
+    private int id;
+
+    public Student(String name, int id){
+        this.name = name;
+        this.id = id;
+    }
+    public String getName(){
+        return name;
+    }
+    public int getId(){
+        return id;
+    }
+    public void setName(String name){
+        this.name = name;
+    }
+    public void setId(int id){
+        this.id = id;
+    }
+}