Question

The program I’ve written is set to only accept positive integers as input. If the user inputs a letter instead, then it crashes. Negative integers don’t cause any problems, though it’s not ‘valid’ in regards to how my program functions.

What I want to do is:

1. Prevent the program from crashing from invalid input.

2. Display an error message if the input is invalid

3. Have the program continue where it left off, without affecting the rest of the program.

Also, a part of my program involves division. Is there a way to prevent the user from entering all zeros?

This is in C#

My code:

using System;

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

namespace OverallCalculator
{

class Program
{
    static void Main(string[] args)
    {
        bool shouldContinue;


        do
        {




            Console.WriteLine("Enter Striking Level: ");

            string striking = Console.ReadLine();

            Console.WriteLine("Enter Grappling Level: ");

            string grappling = Console.ReadLine();

            Console.WriteLine("Enter Submission Level: ");

            string submission = Console.ReadLine();

            Console.WriteLine("Enter Durability Level: ");

            string durability = Console.ReadLine();

            Console.WriteLine("Enter Technical Level: ");

            string technical = Console.ReadLine();

            Console.WriteLine("Enter Speed Level: ");

            string speed = Console.ReadLine();

            Console.WriteLine("Enter Hardcore Level: ");

            string hardcore = Console.ReadLine();

            Console.WriteLine("Enter Charisma Level: ");

            string charisma = Console.ReadLine();




            int gra = Convert.ToInt32(grappling);
            int str = Convert.ToInt32(striking);
            int dur = Convert.ToInt32(durability);
            int spd = Convert.ToInt32(speed);
            int tec = Convert.ToInt32(technical);
            int hdc = Convert.ToInt32(hardcore);
            int cha = Convert.ToInt32(charisma);
            int sub = Convert.ToInt32(submission);

            int total = str + gra + sub + dur + tec + spd + cha + hdc;


            int overall = total / 8 + 8;




            Console.WriteLine("The Overall is " + overall);
            Console.WriteLine("Do you wish to continue? y/n? ");



            if (Console.ReadLine() == "y")
            {
                shouldContinue = true;


            }
            else break;


        } while (shouldContinue == true);
    }
}

}

Answer 1

Here you go:

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

namespace OverallCalculator
{
    class Program
    {
        static void Main(string[] args)
        {
            bool shouldContinue = true;

            while (shouldContinue)
            {
                int strikingLevel = GetValue("Enter Striking Level: ");
                int grapplingLevel = GetValue("Enter Grappling Level: ");
                int submissionLevel = GetValue("Enter Submission Level: ");
                int durabilityLevel = GetValue("Enter Durability Level: ");
                int technicalLevel = GetValue("Enter Technical Level: ");
                int speedLevel = GetValue("Enter Speed Level: ");
                int hardcoreLevel = GetValue("Enter Hardcore Level: ");
                int charismaLevel = GetValue("Enter Charisma Level: ");

                int total = strikingLevel + grapplingLevel + durabilityLevel + submissionLevel +
                    technicalLevel + speedLevel + charismaLevel + hardcoreLevel;

                int overall = total / 8 + 8;

                Console.WriteLine("\nThe Overall is {0}.", overall);
                while (true)
                {
                    Console.WriteLine("Do you wish to continue? y/n? ");
                    string response = Console.ReadLine();
                    if (response.Equals("y", StringComparison.CurrentCultureIgnoreCase) ||
                        response.Equals("yes", StringComparison.CurrentCultureIgnoreCase))
                    {
                        shouldContinue = true;
                        break;
                    }
                    else if (response.Equals("n", StringComparison.CurrentCultureIgnoreCase) ||
                        response.Equals("no", StringComparison.CurrentCultureIgnoreCase))
                    {
                        shouldContinue = false;
                        break;
                    }
                }
            } 
        }

        private static int GetValue(string prompt)
        {
            while (true)
            {
                Console.WriteLine(prompt);
                string input = Console.ReadLine();
                int value;
                if (int.TryParse(input, out value))
                {
                    if (value <= 0)
                        Console.WriteLine("Please enter a positive number.");
                    else
                        return value;
                }
                else
                {
                    Console.WriteLine("Please enter a number.");
                }
            }
        }
    }
}