Calculator using methods

Write a Java Program to make simple Calculator using methods 

import java.util.Scanner;
public class CalculatorUsingMethod 
{
	public int n1,n2;
	public int ans = 0;
	CalculatorUsingMethod()
	{
		Scanner scan = new Scanner(System.in);
		System.out.println("Enter First Number: ");
		n1=scan.nextInt();
		System.out.println("Enter Second Number: ");
		n2=scan.nextInt();
	}
	void add()
	{
		ans=n1+n2;
		System.out.println(n1+" "+ "+" +" "+n2+" = "+ans);
	}
	void sub()
	{
		ans=n1-n2;
		System.out.println(n1+" "+ "-" +" "+n2+" = "+ans);
	}
	void mul()
	{
		ans=n1*n2;
		System.out.println(n1+" "+ "*" +" "+n2+" = "+ans);
	}
	void div()
	{
		ans=n1/n2;
		System.out.println(n1+" "+ "/" +" "+n2+" = "+ans);
	}
	public static void main(String[] args) 
	{
		CalculatorUsingMethod obj = new CalculatorUsingMethod();
		Scanner scan = new Scanner(System.in);
		System.out.println("Enter The Operator (+, -, *, /):  ");
		char operator=scan.next().charAt(0);
		switch(operator)
		{
			case '+' :
				obj.add();
				break;
			case '-' :
				obj.sub();
				break;
			case '*' :
				obj.mul();
				break;
			case '/' :
				obj.div();
				break;
			default:
			System.out.println("You have entered wrong operator...");
		}
	}
}

Output:

Enter First Number: 
30
Enter Second Number: 
5
Enter The Operator (+, -, *, /):  
/
30 / 5 = 6

   

1. Write a Java Program to make simple Calculator using methods
2. Write a Java Program to make simple Calculator using if
3. Write a Java Program to make a Menu Driven Calculator
4. Write a Java Program to make simple Calculator using Equals
5. Write a Java Program to make simple Calculator using switch...case