When Input Values To My Program, It Crashes :( C#

Question

This is the program. Can someone tell me what I did wrong? Every time I input a value for the string SolvingFor, the program crashes. I'm new to coding so if I made a stupid mistake please tell me.

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

namespace PercentageCalculator
{
class Program
{
    static void Main(string[] args)
    {
        string SolvingFor;
        int part;
        int whole;
        int percent;
        Console.WriteLine("please only use numbers and lowercase letters.");
        Console.WriteLine("Are you trying to solve for percent, part, or           whole?");
         SolvingFor = Convert.ToString(Console.Read());

        if (SolvingFor == "part") {
            Console.WriteLine("Please Enter Value of the Whole");
            whole = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Please Enter Value of the Percent");
            percent = Convert.ToInt32(Console.ReadLine()); ;
            Console.WriteLine("Your answer is" + (whole * percent) / 100); }

       else if (SolvingFor == "whole")
        {
            Console.WriteLine("Please Enter Value of the part");
            part = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Please Enter Value of the Percent");
            percent = Convert.ToInt32(Console.ReadLine()); ;
            Console.WriteLine("Your answer is" + (part * 100) / percent);
        }


        else if (SolvingFor == "percent")
        {
            Console.WriteLine("Please Enter Value of the part");
            part = Convert.ToInt32(Console.ReadLine());
            Console.WriteLine("Please Enter Value of the whole");
            whole = Convert.ToInt32(Console.ReadLine()); ;
            Console.WriteLine("Your answer is" + (part * 100) / whole);
        }

        else
        {
            Console.WriteLine("Please only input valid lowercase letters and numbers. ");
        };
        Console.Read();
    }
    }
}

What is the exception and on what line does it happen? Always include the error information. They aren’t just for fun, they tell you what went wrong and often also why. — Sami Kuhmonen, Jan 03 '19 at 20:30
Instead of using `Convert.ToInt32()` to parse user input to get an int. You should use the `int.TryParse()`. Avoid exceptions when you can expect one. _(never trust userinput)_ — Jeroen van Langen, Jan 03 '19 at 20:38

Mohamed Elrashid · Answer 1 · 2019-01-03T20:41:37.210

2

        //SolvingFor = Convert.ToString(Console.Read());
        SolvingFor = Convert.ToString(Console.ReadLine());

if you put(hover) the mouse over ReadLine

you will see that it returns a string so Convert.ToString is not needed

        SolvingFor = Console.ReadLine();

edited Jan 03 '19 at 20:41

answered Jan 03 '19 at 20:34

Mohamed Elrashid

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2

The `Convert.ToString()` isn't needed. – Jeroen van Langen Jan 03 '19 at 20:36
@J.vanLangen yes – Mohamed Elrashid Jan 03 '19 at 20:38

score 1 · Accepted Answer · edited Jan 03 '19 at 20:37

First Issue: Below line from your code is reading just one character.

Instead of Console.Read(), use Console.ReadLine() to enable you to input multiple characters.

 SolvingFor = Convert.ToString(Console.Read());

Second Issue: You are using Convert.ToInt32(Console.Readline());

Please note that Convert.ToInt32 will throw an exception in anything apart from number is provided as input.

Better use int.TryParse which returns if the conversion is successful or not.

When Input Values To My Program, It Crashes :( C#

2 Answers2