// from https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/types/how-to-convert-a-string-to-a-number

​

using System;

​

public class ConvertStringExample1

{

    public static void Main(string[] args)

    {

        int numVal = -1;

        bool repeat = true;

​

        while (repeat)

        {

            Console.Write("Enter a number between −2,147,483,648 and +2,147,483,647 (inclusive): ");

​

            string input = Console.ReadLine();

​

            // ToInt32 can throw FormatException or OverflowException.

            try

            {

                numVal = Convert.ToInt32(input);

                if (numVal < Int32.MaxValue)

                {

                    Console.WriteLine("The new value is {0}", ++numVal);

                }

                else

                {

                    Console.WriteLine("numVal cannot be incremented beyond its current value");

                }

           }

            catch (FormatException)

            {

                Console.WriteLine("Input string is not a sequence of digits.");

            }

            catch (OverflowException)

            {

                Console.WriteLine("The number cannot fit in an Int32.");

            }

​

            Console.Write("Go again? Y/N: ");

            string go = Console.ReadLine();

            if (go.ToUpper() != "Y")

            {

                repeat = false;

            }

        }

    }

}

// Sample Output:

//   Enter a number between -2,147,483,648 and +2,147,483,647 (inclusive): 473

//   The new value is 474

//   Go again? Y/N: y

//   Enter a number between -2,147,483,648 and +2,147,483,647 (inclusive): 2147483647

//   numVal cannot be incremented beyond its current value

//   Go again? Y/N: y

//   Enter a number between -2,147,483,648 and +2,147,483,647 (inclusive): -1000

//   The new value is -999

//   Go again? Y/N: n