The use of exceptions in C#

December 5, 2021

I try to use exception, so that when I input the value for width and length, the negative value is not executable. However, when I input negative value to the width and length, it is still executable. Can you tell me what may be the problem?
Here is my code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rectangle_OOP
{
    public class Program
    {
        double width = 1;
        double length = 1;

        public Program()
        {
        }
        void Checksides(double width, double length)
        {
            if ((width<0) || (length< 0))
            {
                throw new Exception("Rectangle side is not valid");
            }
        }
        public static void Main(String[] args)
        {
            Program obj = new();
            obj.width = double.Parse(Console.ReadLine());
            obj.length = double.Parse(Console.ReadLine());
            double area = obj.width * obj.length;
            Console.WriteLine(area);
        }
    }
}

>Solution :

The Checksides is never invoked

Simply change the Main method as follows

public static void Main(String[] args)
{
    Program obj = new();
    obj.width = double.Parse(Console.ReadLine());
    obj.length = double.Parse(Console.ReadLine());

    // Invoke the Checksides method 
    Checksides(obj.width, obj.length);

    double area = obj.width * obj.length;
    Console.WriteLine(area);
}

Fabio