using System;

public class Program

{

    public static void palindrome(int num)

    {

        String s="",s1="";

        s=Convert.ToString(num);

        for(int i=s.Length-1;i>=0;i--)

            s1+=s[i];

        if(s==s1)

            Console.WriteLine("It is a palindrome");

        else    

            Console.WriteLine("It is not a palindrome");

    }

    public static void noofdigit(int num)

    {

        int count=0;

        while(num>0)

        {

            num/=10;

            count+=1;

        }

        Console.WriteLine("The no of digits are "+count);

    }

    public static void fibo(int n)

    {

        int n1=1,n2=2,sum=0;

        Console.Write(n1+"    "+n2);

        while(sum<n)

        {

            sum=n1+n2;

            if(sum<n)

                Console.Write("    "+sum);

            n1=n2;

            n2=sum;

        }

    }

    public static void Main()

    {

        String mid="";

        do{

        Console.WriteLine("Enter your choice");

        Console.WriteLine("1:Palindrome check" +"2:total number of digits"+"3:print fibonacci series"+"4:exit");

        int check=int.Parse(Console.ReadLine());

        switch(check)

        {

            case 1:Console.WriteLine("Enter number");

                   int num=int.Parse(Console.ReadLine());

                    palindrome(num);

                    break;

            case 2:Console.WriteLine("Enter number");

                    int num1=int.Parse(Console.ReadLine());

                    noofdigit(num1);

                    break;

            case 3:Console.WriteLine("enter number");

                    int num2=int.Parse(Console.ReadLine());

                    fibo(num2);

                    break;

            case 4:

            default: Console.WriteLine("Exit done");

                    break;

        }

            Console.WriteLine("Do you want to continue(y/n)");

            mid=Console.ReadLine();

        }while(mid=="y");   

        }

    }

​