How to read Object list item in C#

Question

I have a object that prints a multidimensional matrix, eg:

 namespace example;

    Public class Object()
    {
        int lines, cols;
        int matrix[,];
        public Object(int lines, int cols)
        {
            this.lines = lines;
            this.cols = cols;
            matrix = new int[lines,cols];

            PrintMatrix()
        }

        public void PrintMatrix()
        {
            Random rand = new Random();
            Console.WriteLine();
            for(int i = 0; i < lines ;i++)
                for(int j = 0, j < cols; j++)
                    matrix[i,j]= rand.nextInt(1,10);
                Console.WriteLine(matrix[i,j));
        }

    }

i want to print in console output something like this:

    matrix 1:
     1 2 3
     4 2 4
     3 3 1

    matrix 2:
     2 3 4 4
     1 1 2 2
     3 3 4 4
     1 1 8 8


matix 3:
 ...

So i have tried to insert the Object inside of List or Arraylist:

static void Main(string[] args)
 {
     List<Object> conteiner = new List<Object>();

     Object foo = new Object(3,3);
     Object anotherFoo = new Object(4,4);

     conteiner.add(foo);
     conteiner.add(anotherFoo);

     foreach(object item in conteiner)
     {
         console.WriteLine(item)
     }   
 }

it prints :

 example.Object.foo;
 example.Object.anotherFoo;

instead of multidimentional arrays. What I´m doing wrong and how can i improve this solution?

Answer 1

If you want you could override the default ToString() method of your object.

 public override string ToString()
 {
     return PrintMatrix();
 }

Of course this forces you to make PrintMatrix() return a string but I would suggest to do it that way as it makes for better because more reusable code.

I would write something like the following :

public string PrintMatrix()
{
    string result = string.Empty;

    for(int i = 0; i < lines ;i++)
    {
        for(int j = 0, j < cols; j++)
        {
            matrix[i,j] = rand.Next(1,10);
            result += $"{matrix[i,j]} ";
        }
        result +=  Environment.NewLine ;
    }

    return result;
}

By the way if you're wondering why your numbers are't random try creating only one Random object. You can then use it as you're doing now.

Answer 2

Cause you are printing the type itself which calls it's default ToString() instead you should do call PrintMatrix() on every object instance. As well consider giving a better name to your type than Object since that's a built-in type

 foreach(Object item in conteiner)
 {
   item.PrintMatrix();
 }