import java.lang.reflect.Method;

import java.util.Scanner;

class Calculator{

public int add(int x, int y){

return x + y;

}

public int subtract(int x, int y){

return x - y;

}

public int multiply(int x, int y){

return x * y;

}

public int divide(int x, int y){

return x / y;

}

}

public class CalcDemo {

public static void main(String[] args) throws Exception{

Scanner scanner = new Scanner(System.in);

System.out.println("Enter the First No");

int firstNo = scanner.nextInt();

System.out.println("Enter the Second No");

int secondNo = scanner.nextInt();

System.out.println("Enter the Operation (add,subtract,multiply,divide) ");

String operation = scanner.next();

//Calculator calc = new Calculator();

int result = 0;

Object object = Class.forName("Calculator").newInstance();

Method method = object.getClass()

.getDeclaredMethod(operation, int.class,int.class);

// Downcasting + AutoBoxing

result = (Integer)method.invoke(object, firstNo,secondNo);

/*if(operation.equals("add")){

result = calc.add(firstNo, secondNo);

}

else

if(operation.equals("subtract")){

result = calc.subtract(firstNo, secondNo);

}

else

if(operation.equals("multiple")){

result = calc.multiply(firstNo, secondNo);

}

else

if(operation.equals("divide")){

result = calc.divide(firstNo, secondNo);

}*/

System.out.println("Result is "+result);

}

}