// delete employee func for the validation
        static void deleteTheEmployee(EmployeeMgtSys employee)
        {
            //  welcome del func
            System.Console.WriteLine("\nEnter the employees's first name that you want to delete?");
            var userDelInput = Console.ReadLine().ToLower();

            EmployeeGenericFunc.regexChecker
                (userDelInput);
            var delEmployee = employee.deleteEmployee(userDelInput);

            // employee display
            EmployeeGenericFunc.displayEmployee(delEmployee, userDelInput, "deleted");
        }
        // search for employee func and validation of type
        static void searchTheEmployee(EmployeeMgtSys employee)
        {
            //  welcome search func
            System.Console.WriteLine("\nHow would you like to search an employee today \nTo search by firstname enter firstname");
            var nameSearchInput = System.Console.ReadLine().ToLower();

            if (EmployeeGenericFunc.regexChecker(nameSearchInput) == null)
            {
                System.Console.WriteLine("\nPlease enter valid type");
            }
            else
            {
                var searchResult = employee.searchEmployee(nameSearchInput);
                EmployeeGenericFunc.displayEmployee(searchResult, nameSearchInput, "founded");
            }
        }
        // validation fo data type for add employee
        static void addTheEmployee(EmployeeMgtSys employee)
        {
            //  welcome add func
            System.Console.WriteLine("\nPlease add some details to add an employee in our directoryEnter first Name\n");
            var firstName = Console.ReadLine();

            EmployeeGenericFunc.regexChecker(firstName);

            System.Console.WriteLine("Enter last Name\n");
            var lastName = Console.ReadLine();

            EmployeeGenericFunc.regexChecker(lastName);

            System.Console.WriteLine("Enter age\n");
            var age = Console.ReadLine();
            // var ageInt =Convert.ToInt32(regexChecker
            var ageInt = EmployeeGenericFunc.intChecker(age);

            System.Console.WriteLine("Enter Designation\n");
            var designation = Console.ReadLine();

            EmployeeGenericFunc.regexChecker(designation);

            System.Console.WriteLine("Enter Employee's Salary\n");
            var salary    = Console.ReadLine();
            var salaryInt = EmployeeGenericFunc.intChecker(salary);

            if (firstName == null || lastName == null || ageInt == 0 || designation == null || salaryInt == 0)
            {
                System.Console.WriteLine("\nPlease enter valid type");
                return;
            }
            else
            {
                var employeeAdded = employee.addEmployee(firstName, lastName, ageInt, designation, salaryInt);
                // employee display
                EmployeeGenericFunc.displayEmployee(employeeAdded, employeeAdded.FirstName, "added");
            }
        }