Calculator in Switch Statement in C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.Write("Enter Your Name:  ");
            string name = Console.ReadLine();
            switch (name) //switching on 'name' value.
            {
                case "Bilal": //if 'name' have 'Bilal' OR 'Amir' OR
                case "Amir":  //'Zulfi' OR 'Huzaif' value then
                case "Zulfi":
                case "Huzaif":
                    Console.Write("U R Project Director in IT Park!!!"); //print this.
                    break; //and Break the process.
                case "Nawaz": //if 'name' have 'Nawaz' OR 'Ali' OR
                case "Ali": //'Zaheer' OR 'Inam' value then
                case "Zaheer":
                case "Inam":
                    Console.Write("U R Worker in IT Park!!"); //print this.
                    break; //and Break the process.
                default: //if not in Above then
                            Console.Write("I Don't Know U!"); //print this.
                            break; //and Break the process.
            }
            Console.ReadKey();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            int a, b;
            string op; //for operator I use string.
            Console.WriteLine("Please Enter first number");
             a = Int32.Parse(Console.ReadLine());
             Console.WriteLine("Please Enter Operator + , - , * , /");
             op = Console.ReadLine();
             Console.WriteLine("Please Enter 2nd number");
             b = Int32.Parse(Console.ReadLine());
            switch (op)
            {
                case "+": //if 'op' have '+' value then
                    Console.WriteLine("Addition  {0}", a+b); //add and print 'a' and 'b' values.
                    break;
                case "-":
                    Console.WriteLine("Subtraction  {0}", a-b);
                    break;
                case "*":
                    Console.WriteLine("Multiplication {0} ", a*b);
                    break;
                case "/":
                    Console.WriteLine("Division {0} ", a/b);
                    break;
            }
            Console.ReadLine();
        }
    }
}