CODEWITHSUNDEEP
c#
user3365114
user3365114

Reputation: 91

Accessing element array

Okay, I have made another program to be a bit clearer about my problem. I have an object array containing int arrays and I am trying to print the index[0] from the element neuron one. However, I am getting a null reference exception at the line 'Console.WriteLine(ex.neuron[0])' My code is below.

 namespace ConsoleApplication5
  {
class Program
{

    static void Main()

    {
        ex ex = new ex();

        int[]neuron1 = new int[5];
        int[]neuron2 = new int[5];
        int[]neuron3 = new int[5];
        int[]neuron4 = new int[5];
        int[]neuron5 = new int[5];



        object[,] array1 = new object[2,2];
        array1[0, 0] = ex.neuron1;
        neuron1[0] = 1;

        array1[0, 1] = neuron2;
        neuron2[1] = 1;

        test(array1);

    }

    static void test(object[,] array1)
    {
           ex ex = new ex();
           Console.WriteLine(ex.neuron1[0]);
           Console.ReadLine();
    }
}

}

I have a class getting and setting neuron1 here:

    static void test(object[,] array1)
    {
           ex ex = new ex();
           Console.WriteLine(ex.neuron1[0]);
           Console.ReadLine();
    }
}

}

I think that the exception is occurring as I am accessing ex.neuron[0] before it has been defined as containing the value one. So my question is how do I access ex.neuron[0] after is has been set as holding the value one. Thanks.

Upvotes: 0

Views: 213

Answers (2)

Cᴏʀʏ
Cᴏʀʏ

Reputation: 107498

You're creating a new instance of ex in each function, when you probably just need to pass it along instead. Also, you never set up the neuron fields on the instance itself. Here is a simplified version of your code:

static void Main()
{
    // define it here
    ex ex = new ex();

    // initialize the neuron fields (although you should probably do this
    // in the constructor for ex
    ex.neuron1 = new int[5];
    ex.neuron2 = new int[5];
    ex.neuron3 = new int[5];
    ex.neuron4 = new int[5];
    ex.neuron5 = new int[5];

    // set some neuron array values
    ex.neuron1[0] = 1;
    ex.neuron2[1] = 1;

    // pass the instance along to test
    test(ex);
}

static void test(ex ex)
{
    // access the array value here
    Console.WriteLine(ex.neuron1[0]);
    Console.ReadLine();
}

Upvotes: 1

dwonisch
dwonisch

Reputation: 5785

you never set ex.neuron1, replace these lines

int[] neuron1 = new int[5];

with

ex.neuron1 = new int[5];

Upvotes: 1

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