Returns simplify as null

Question

So, First of all, I'm a beginner, and 6 months of experience in C# at school. I can do it the other way, but I want to know more ways to do stuffs so.. And I need help about this. What happens is, when i run the program everything goes okay until private void Add(), some error comes up and says that Simplify is null? Thanks in advance.

using System;

namespace test1
{
 class Details
 {
    int NumberSimplify;
    double Solution;

    private void Ask()
    {
        Console.Write("Would you like to Add or Substract (1 - Add, 2 - Substract) -► ");
        int Opt = int.Parse(Console.ReadLine());

        switch(Opt)
        {
            case 1:
                Console.Write("\nHow many numbers would you like to add? -► ");
                NumberSimplify = int.Parse(Console.ReadLine());                    
                break;

            case 2:
                break;
        }
    }

    public void DisplayResult(double[] Simplify)
    {
        Console.Write("Result from Addition -► ", Add(Simplify));
    }

    private void AddDetails()
    {
        Ask();
        double[] Simplify = new double[NumberSimplify];
        Console.WriteLine();
        for (int i = 0; i < Simplify.Length; i++)
        {
            Console.Write("Number {0} -► ", i + 1);
            Simplify[i] = double.Parse(Console.ReadLine());
        }
    }



    private double Add(double[] Simplify)
    {
        AddDetails();
        for (int i = 0; i < Simplify.Length; i++)
        {
            Solution = Simplify[i] + Simplify[i + 1];
        }
        return Solution;
    }


}


class Execute
{
    public static double[] Simplify { get; private set; }

    static void Main(string[] args)
    {

        Details AddOrSub = new Details();
        AddOrSub.DisplayResult(Simplify);
        Console.ReadLine();

    }
}

}

Can you please clarify of which `Simplify` you´re talking? Where exactly do you get `null`? — MakePeaceGreatAgain, Jul 07 '17 at 13:21
BTW `AddDetails` is not going to change the same `Simplify` array that is passed into `Add` — juharr, Jul 07 '17 at 13:24
You have a couple of different variables called `Simplify`. Which one is `null`? Where do you initialize that one? — David, Jul 07 '17 at 13:25
`for (int i = 0; i < Simplify.Length; i++) { Solution = Simplify[i] + Simplify[i + 1]; }` Will give trow an exception as well. It must be Length-1 — RoJaIt, Jul 07 '17 at 13:26
Really you don't need the `Simplify` array in `Execute` Just return the one you create in `AddDetails` back to `Add`. Also your `Add` method is going to give you an out of range exception because of `Simplify[i+1]`. If you just want the sum then do `Solution += Simplify[i];` instead. — juharr, Jul 07 '17 at 13:27
`Console.Write("Result from Addition -► ", Add(Simplify));` would not print result at console. Change it to `Console.Write("Result from Addition -► {0} ", Add(Simplify));` — mmushtaq, Jul 07 '17 at 13:41
Simplify probably becomes null from the start since I did not gave it a size, but it changes on the AddDetails() because of NumberSimplify and returns to normal in Add() — dotke, Jul 07 '17 at 13:43
@mmushtaq yes.. but the issue here was the array, still thanks for pointing it out! — dotke, Jul 07 '17 at 13:45
[Here](https://dotnetfiddle.net/qrC9JG) is working .Net Fiddle of your code. — mmushtaq, Jul 07 '17 at 13:53

Milney · Answer 1 · 2017-07-07T13:25:36.457

3

Simplify is indeed null....

public static double[] Simplify { get; private set; }

You need to initialize arrays... so this should be more like;

public static double[] Simplify { get; private set; } = new double[someNumberOfElements]

But as pointed out in the comments, you dont even use this initial version of the variable (It is overwritten anyway in your next methods) so consider removing it altogether and re-visiting your control flow...

edited Jul 07 '17 at 13:25

answered Jul 07 '17 at 13:21

Milney

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The size is asked on the first class, how do I pass it on the second? – dotke Jul 07 '17 at 13:24
You don't need to... just dont even have that in the Execute class, you don't use it anway... – Milney Jul 07 '17 at 13:26
If I don't use it, AddOrSub.DisplayResult(Simplify); gives an error, Simplify inside the parentheses is red – dotke Jul 07 '17 at 13:31
"Doesn't exist in the current context" – dotke Jul 07 '17 at 13:31
Yes - you can take it out of there too, and out of the method DisplayResult – Milney Jul 07 '17 at 13:31
Because you don't use it anyway... try follow the flow through and you will see – Milney Jul 07 '17 at 13:32
But now, in DisplayResult method, it says the same, doesn't exist – dotke Jul 07 '17 at 13:34
Thank you, it worked now, I simply removed the array and did some adjustments, works fine now! – dotke Jul 07 '17 at 13:51

Returns simplify as null

1 Answers1