array maths

[mrcw]

if I have an 2 dimensional array eg

int[,] numbers = new int[3, 2] { {1, 2}, {3, 4}, {5, 6} };

how do I add 8 to the first item of the third row eg 5 to make

[3, 2] { {1, 2}, {3, 4}, {13, 6} };

thnx
mrcw

[tlhintoq]

Your initializer creates the following:
numbers[0,0] = 1
numbers[0,1] = 2
numbers[1,0] = 3
numbers[1,1] = 4
numbers[2,0] = 5
numbers[2,1] = 6

So to add 8 to the first item of the third row:
numbers[2,0] = numbers[2,0] + 8;

[GaryTexmo]

You need to access the appropriate index for that item. In C#, array indexes start at zero, so according to your setup the third row would be index 2, and the first item of that row would be index 0.

numbers[2,0] += 8;
// or...
numbers[2,0] = numbers[2][0] + 8;

Here's the MSDN page on multidimensiona l arrays...
http://msdn.microsoft.com/en-us/libr...8VS.71%29.aspx

*Edit: Ahhh look at me, getting caught up by syntax. Fixed!

[mrcw]

can I use that code in a windows form application ? It works fine as a console application, but as a wpa it gives me lots of nonsense errors

mrcw

[tlhintoq]

It should work fine. Please provide a copy of the code from your app along with the error message

[mrcw]

int[,] numbers = new int[3, 2] { { 1, 2 }, { 3, 4 }, { 5, 6 } }; is fine -no errors


numbers[2, 0] = numbers[2, 0] + 8; red wriggly line under both 2, = and +

Error 1 Array size cannot be specified in a variable declaration (try initializing with a 'new' expression)

Error 2 Invalid token '=' in class, struct, or interface member declaration

Error 3 Array size cannot be specified in a variable declaration (try initializing with a 'new' expression)

Error 4 Invalid token '+' in class, struct, or interface member declaration

[tlhintoq]

As was earlier suggested, try it as numbers[2][0]

[mrcw]

hi

I am trying the examples from http://msdn.microsoft.com/en-us/library/2yd9wwz4.aspx

This gives me 11 errors that are copies of the ones I gave before
I still qustion "can I use arrays in wpa? It does appear not.

mrcw

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;


namespace Arrays1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


         int[,] numbers = new int[3, 2] { { 1, 2 }, { 3, 4 }, { 5, 6 } };
         numbers[2, 0] = numbers[2][0] + 8;

        //int[,] myArray = new int[4,2];
        // int[,] myArray = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };

         int[,] myArray = { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
         myArray[1,0] = myArray[1,3] + 5;

         int[,] array2D = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
         array2D[2 ,1 ] = 25;


         //int[,] array5;
         //array5 = new int[,] { { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } }; 
         //array5[2, 1] = 25;

         int[,] array6 = new int[10, 10];

    }
}[