Feature/calculator

src/main/java/com/thealgorithms/Calculator.java

@@ -0,0 +1,16 @@
+public class Calculator {
+    // ADDITION
+    public double add(double a, double b) { return a + b; }
+    // SUBTRACTION
+    public double sub(double a, double b) { return a - b; }
+    // MULTIPLICATION
+    public double mul(double a, double b) { return a * b; }
+    // DIVISION
+    public double div(double a, double b) {
+        if (b == 0) {
+            System.out.println("Error: Division by zero!");
+            return 0;
+        }
+        return a / b;
+    }
+}

src/main/java/com/thealgorithms/Student.java

@@ -0,0 +1,37 @@
+public class Student {
+    private String name;
+    private int roll;
+    private String dept;
+    private String batch;
+
+    // DEFAULT CONSTRUCTOR
+    public Student() {}
+
+    // PARAMETERIZED CONSTRUCTOR
+    public Student(String name, int roll, String dept, String batch) {
+        this.name = name;
+        this.roll = roll;
+        this.dept = dept;
+        this.batch = batch;
+    }
+
+    // COPY CONSTRUCTOR
+    public Student(Student student) {
+        this.name = student.getName();
+        this.roll = student.getRoll();
+        this.dept = student.getDept();
+        this.batch = student.getBatch();
+    }
+
+    // GETTERS
+    public String getName() { return name; }
+    public int getRoll() { return roll; }
+    public String getDept() { return dept; }
+    public String getBatch() { return batch; }
+
+    // SETTERS
+    public void setName(String name) { this.name = name; }
+    public void setRoll(int roll) { this.roll = roll; }
+    public void setDept(String dept) { this.dept = dept; }
+    public void setBatch(String batch) { this.batch = batch; }
+}