C#: How to write another function for this code?

Question

How would I write another function named noNegatives for this code? I want to rewrite the code with another function named noNegatives but I still want the program to do the same thing.

    class Program
    {
        static void Main(string[] args)
        {
            string numberIn;
            int numberOut;

            numberIn = Console.ReadLine();

            while (!int.TryParse(numberIn, out numberOut) || numberOut < 0)
            {
                Console.WriteLine("Invalid. Enter a number that's 0 or higher.");
                numberIn = Console.ReadLine();
            }
        }       
    }

`void noNegatives(){}` fulfills what you've asked. What should the function do? — Tim S., Oct 05 '13 at 12:46
I want to rewrite the code with another function named noNegatives but I still want the program to do the same thing. — User, Oct 05 '13 at 12:52

C Sharper · Answer 1 · 2013-10-05T13:05:44.873

Follwing is the simplest way you can write it

static void Main(string[] args)
            {
                int retVal=0; 
                string numberIn;
                int numberOut;
                numberIn = Console.ReadLine();

                while(noNegatives(numberIn,numberOut)=0)
                {

                }
             } 

    int noNegatives(String numberIn,int numberOut)
    {


                numberIn = Console.ReadLine();

                if (!int.TryParse(numberIn, out numberOut) || numberOut < 0)
                {
                    Console.WriteLine("Invalid. Enter a number that's 0 or higher.");
                    return 0;

                }
                else
                {
                   return 1;
                }
    }

As written, your code won't work. I'd go with a signature of `int noNegatives()`. — Tim S., Oct 05 '13 at 12:59

score 0 · Accepted Answer · answered Oct 05 '13 at 13:02

static void Main(string[] args)
{
    int number = NoNegatives();
}
static int NoNegatives()
{
    int numberOut;

    string numberIn = Console.ReadLine();

    while (!int.TryParse(numberIn, out numberOut) || numberOut < 0)
    {
        Console.WriteLine("Invalid. Enter a number that's 0 or higher.");
        numberIn = Console.ReadLine();
    }
    return numberOut;
}

score 0 · Answer 3 · edited May 23 '17 at 12:03

This question is very similar to the one posted here.

    static void Main(string[] args)
    {
        string numberIn = Console.ReadLine();
        int numberOut;

        while(!IsNumeric(numberIn))
        {
            Console.WriteLine("Invalid.  Enter a number that's 0 or higher.");
            numberIn = Console.ReadLine();
        }
        numberOut = int.Parse(numberIn);
    }

    private static bool IsNumeric(string num)
    {
        return num.ToCharArray().Where(x => !Char.IsDigit(x)).Count() == 0;
    }

Since the negative sign is not a digit, IsNumeric will return false for negative numbers.

C#: How to write another function for this code?

3 Answers3