CODEWITHSUNDEEP
c#
Brendan X
Brendan X

Reputation: 11

C# input has to be 5 digits

I have a question that asks the user to enter a student number, how can I make it so it will only accept a 5 digit number. The input is being added to an object like 

console.writeline("Enter the student number: ");

then 

studentObject.StudentNumber = int.Parse(Console.Readline());

I've tried using 

if (Console.ReadLine().Length != 5)
{

  //Do this
}
else
{
   //Do this
}

But it won't work, the .Length says can't convert type int to bool. I'm stuck, any help please?

Upvotes: 1

Views: 5486

Answers (4)

CowardlyDog
CowardlyDog

Reputation: 1

char[] cc = Console.Read().ToString().ToCharArray(); 
            if (char.IsDigit(cc[0])&&
                char.IsDigit(cc[1])&&
                char.IsDigit(cc[2])&&
                char.IsDigit(cc[3])&&
                char.IsDigit(cc[4]))
            {
                //Life's GOOD!
            }else { //bad input}

Note: I'm self-taught & don't have much knowledge. Correct me if wrong.

Upvotes: 0

Dmitrii Bychenko
Dmitrii Bychenko

Reputation: 186748

You can use regular expressions:

  String input;

  do {
    Console.WriteLine("Please enter student number:");
    input = Console.ReadLine();
  }
  while (!Regex.IsMatch(input, @"^\d{5}$")); // <- five digits expected

  // input contains 5 digit string
  int number = int.Parse(number);

P.S. In case that the input should be "five digit number, not starting with zero" the regular expression has to be changed to something like that:

 while (!Regex.IsMatch("12345", @"^[1-9]\d{4}$")); // five digits, not zero-starting

Upvotes: 3

pradeep varma
pradeep varma

Reputation: 136

 var input = Console.ReadLine();
  int i;
 if (input.Length > 0 && input.Length < 6 && Int32.TryParse(input, out i))
                    // i has 5 digit;
                    else
                 // i has zero

Upvotes: 0

JanR
JanR

Reputation: 6132

Probably not the answer to your question, however one thing I noticed:

if you are using Console.Readline() in your if-statement and then want to store it in the studentObject you will need to store it in a variable first. Calling Console.Readline(); again to store it in the studentObject will cause another input to be expected, which nullifies your attempt to validate the input.

Something like this:

    static void Main(string[] args)
    {
        Console.WriteLine("Please enter student number:");

        //get the user input
        var number = Console.ReadLine();

        if (number.Length != 5)
        {

            Console.WriteLine("Invalid format.");
        }
        else
        {

            Console.WriteLine("Yay it works");
        }
        Console.ReadLine();

    }

Upvotes: 0

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