I have a question about Re-Entering Try Catch

[patrick]

Hello

I have a question about Re-Entering Try Catch

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            int iNum1;
            int iNum2;
            while (true)
            {
                try
                {
                    Console.WriteLine("1) Please Input Integer ----1");
                    iNum1 = int.Parse(Console.ReadLine());


                    Console.WriteLine("2) Please Input Integer ----2");
                    iNum2 = int.Parse(Console.ReadLine());

                    break;
                }
                catch (Exception)
                {
                    Console.WriteLine("An integer was not entered");
                }
            }
        }
    }
}

Thank you

 

[Skydiver]

Pros will use int.TryParse().

Do not use try-catch for flow control. It makes code much harder to understand because of the implicit jumps that can happen. It's basically like having evil gotos without explicitly writing goto.

 

[Skydiver]

Anyway, write a helper method that uses TryParse(). The pseudo-code would look something like:

int PromptForInt(string prompt)
{
    while (true)
    {
        Console.WriteLine(prompt);
        var input = Console.WriteLine();
        if (int.TryParse(input, out int value))
            return value;
        Console.WriteLine("Invalid integer entered.");
    }
}

:

var iNum1 = PromptForInput("Enter the first number");
var iNum2 = PromptForInput("Enter the second number");

 

[kareninstructor]

Check out Spectre..Console. In the code below the generic method Get only accepts int, not decimal or double. If they press ENTER the default value of 0 is set to the variable.

using System;
using Spectre.Console;

namespace ConsoleApp1
{
    internal partial class Program
    {
        static void Main(string[] args)
        {
            int value1 = Get("Please enter first number", 0);
            int value2 = Get("Please enter second number", 0);
            Console.WriteLine($"{value1,-5}{value2}");
            Console.WriteLine("Press ENTER to Exit");
            Console.ReadLine();
        }

        internal static T Get<T>(string prompt, T defaultValue)
        {
            return AnsiConsole.Prompt(
                new TextPrompt<T>($"[white]{prompt}[/]")
                    .PromptStyle("white")
                    .DefaultValueStyle(new(Color.Yellow))
                    .DefaultValue(defaultValue)
                    .ValidationErrorMessage("[white on red]Invalid entry![/]"));
        }
    }
}

 

[cjard]

Yes, but.. OP can't work out Console.ReadLine and you're recommending generics?

 

[Skydiver]

Karen probably doesn't remember the drama of past Patrick/Anwind threads.

 

[ItzSuri]

Anyway, write a helper method that uses TryParse(). The pseudo-code would look something like:

var input = Console.WriteLine();

Shouldn't it be?

var input = Console.ReadLine();

I might be wrong, because I am also a beginner and might have missed something.

 

[Skydiver]

That's right. It should be ReadLine().