Question

How to check if a string is a positive number, negative number or not a number in C#

Answer 1

using System;

public class Program
{
    public static string PositiveOrNegative (string s) {
        try  {
            double n = double.Parse(s);
            if (n < 0) {
                return "negative";
            }
            else {
                return "positive";
            }
        }
        catch (FormatException) {
            return "not a number";
        }
    }

    public static void Main(string[] args)
    {
        string s = "84593";
        Console.WriteLine(PositiveOrNegative(s));

        s = "-15";
        Console.WriteLine(PositiveOrNegative(s));

        s = "18W";
        Console.WriteLine(PositiveOrNegative(s));
    }
}

 
 
/*
run:

positive
negative
not a number
 
*/

 

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