tax-calculator.cs

using System;

namespace TaxCalculator
{
    class TaxCalculator
    {
        static void Main(string[] args)
        {
            int salary; 

            while(true)
            {   
                Console.WriteLine("Enter salary: ");
                var isNumber = int.TryParse(Console.ReadLine(), out salary);
                
                if(!isNumber || salary < 1)
                {
                    Console.WriteLine("Invalid salary. Try again.");
                    continue; 
                }

                var netSalary = ApplyTax(Convert.ToDecimal(salary));
                Console.WriteLine($"Net salary: {netSalary}");
                break;
            }
        }

        static decimal ApplyTax(decimal salary)
        {
            decimal incomeTax = 0.10M;
            decimal socialTax = 0.15M;

            //If salary is more than 1000 apply income tax
            if(salary > 1000)
            {
                salary -= incomeTax * salary;
                //If salary is less than 3000 apply social contribution tax
                if(salary < 3000)
                {
                    salary -= socialTax * salary;
                }
            }

            return System.Math.Round(salary, 2); 
        }
    }
}