How to count digits of number without loop?-CodePudding

I am trying to make an app where you can add phone numbers and other stuff and I want to check if the number is in correct format so i have been using this loop to check this

int numer = int.Parse(Console.ReadLine());
int count = 0;
int number = numer;

while (number > 0)
{
    number /= 10;
    count  ;

    if (number)
    {
        Console.WriteLine(count);
        stringList.Add(nazwa);
        intList.Add(numer);
        //Console.Clear();
        Console.WriteLine($"You added new contact {nazwa} which number is {numer} ");
        Console.WriteLine();
        

    }
    else
    {
        Console.WriteLine(count);
        //Console.Clear();
         Console.WriteLine("This number is in a wrong format!");
         Console.WriteLine();

    }
}

The problem is when i will type number that has 10 digits program will add this number to the database and after that is going to send error to the user.

CodePudding user response：

To validate it you just need:

string input = Console.ReadLine();
bool valid = input.Length == 10 && input.All(char.IsDigit);

I just saw that you want to validate phone-numbers. Well, then this is not sufficient. But if a phone number is valid depends on the country/region. Search for phone number regex(for example in US).