We Keep Coding

No. of rows 1 less than expected in a jagged array

While printing this jagged array I am getting the no of rows to be 1 less than expected. It should start with 0th index to (h-1)th index creating a total of h rows. What am I doing wrong?
h is the no. of rows.
int h = int.Parse(Console.ReadLine());
int[][] arr = new int[h][];
for(int i = 0; i < h; ++i)
{
arr[i] = new int[i+1];
}
for(int i = 0; i < h; i++)
{
Console.WriteLine();
for(int j = 0; j < i; j++)
{
Console.Write(arr[i][j] + " ");
}
}

That's because your inner for-loop has the condition j < i. If i is 0 in the first pass, the inner for-loop will not be passed.
Try it with
for(int j = 0; j < arr[i].Length; j++)
{
Console.Write(arr[i][j] + " ");
}

The arrays have a growing list of elements, starting with 1 so if you want to scan all the items:
for(int i = 0; i < h; i++)
{
Console.WriteLine();
for(int j = 0; j < (i + 1); j++)
{
Console.Write(arr[i][j] + " ");
}
}

Shouldn't it be:
new int[i];
Instead of:
new int[i+1]
Or is it h - 1? Just change that index of the array.
Or you need j < arr[i].Length

Why there is "index exceeded the number of group boundaries" in this code?

For this code in Visual Studio
Point[,] point = new Point[9, 10];
for (int i = 0; i < 9; i++)
{
for(int j = 0; i < 10; j++)
{
point[i, j].X = i;//mark1
point[i, j].Y = j;
}
}
at //mark1,system tell me"index exceeded the number of group boundaries"
Why?

you are doing
for (int j = 0; i < 10; j++)
so the condition i < 10 which is maybe a typo is causing your loop to go out of the range in the array (you are then trying to access the eleement 0, 10 in the array)
replace that with:
for (int j = 0; j < 10; j++)

Change 2d array bubble sort to counting sort

The following code sorts rows by the first element using bubble method.
I can't change it to counting sort.
public void SortStack(double[,] n)
{
for (int i = 0; i < n.GetLength(0) - 1; i++)
{
for (int j = i; j < n.GetLength(0); j++)
{
if (n[i, 0] > n[j, 0])
{
for (int k = 0; k < n.GetLength(1); k++)
{
var temp = n[i, k];
n[i, k] = n[j, k];
n[j, k] = temp;
}
}
}
}
}
Please help.

As you do bubble sort based on first element of each row. you should do counting sort like that too. so you just need to count first item of each row.
private static int[,] CountingSort2D(int[,] arr)
{
// find the max number by first item of each row
int max = arr[0, 0];
for (int i = 0; i < arr.GetLength(0); i++)
{
if (arr[i, 0] > max) max = arr[i, 0];
}
// we want to get count of first items of each row. thus we need 1d array.
int[] counts = new int[max + 1];
// do the counting. again on first index of each row
for (int i = 0; i < arr.GetLength(0); i++)
{
counts[arr[i, 0]]++;
}
for (int i = 1; i < counts.Length; i++)
{
counts[i] += counts[i - 1];
}
// result is sorted array
int[,] result = new int[arr.GetLength(0), arr.GetLength(1)];
for (int i = arr.GetLength(0) - 1; i >= 0; i--)
{
counts[arr[i, 0]]--;
// now we need to copy columns too. thus we need another loop
for (int j = 0; j < arr.GetLength(1); j++)
{
result[counts[arr[i, 0]], j] = arr[i, j];
}
}
return result;
}
Here is the test.
static void Main()
{
Random rand = new Random();
int[,] arr = new int[3,3];
for (int i = 0; i < 3; i++)
{
for (int j = 0; j < 3; j++)
{
arr[i, j] = rand.Next(0, 100);
}
}
int[,] newarr = CountingSort2D(arr);
for (int i = 0; i < arr.GetLength(0); i++)
{
Console.Write("{ ");
for (int j = 0; j < arr.GetLength(1); j++)
{
Console.Write(arr[i, j] + " ,");
}
Console.Write("} ,");
}
Console.WriteLine();
for (int i = 0; i < newarr.GetLength(0); i++)
{
Console.Write("{ ");
for (int j = 0; j < newarr.GetLength(1); j++)
{
Console.Write(newarr[i, j] + " ,");
}
Console.Write("} ,");
}
Console.WriteLine();
}
Example Output:
{ 49,66,8 },{ 33,39,64 },{ 65,52,76 } // Original array
{ 33,39,64 },{ 49,66,8 },{ 65,52,76 } // Sorted array

C# How to Print 2 arrays together

Ok, so lets say i have two arrays like these;
int[] wow = new int[50];
for (int j = 0; j < wow.Length; j++)
{
wow[j] = j + 1;
}
int[] wew = new int[50];
for (int i = 0; i < wew.Length; i++)
{
wew[i] = i + 10;
}
and i want to print them like;
1 , 11
2 , 12
3 , 13

for (int j = 0; j < wow.Length; j++)
{
wow1[j] = j + 1;
wow2[j] = j + 10;
//print wow1 & wow2 here.
Console.WriteLine("{0},{1}", wow1[j], wow2[j]);
}
Note that in your two loops, i is no different with j, they are essentially the same!

How about using two for-loops?
for(int i = 0; i < wow.Length;i++)
{
for(int j = 0; j < wew.Length;i++)
{
//Print
Console.WriteLine("{0} , {1}", wow[i].ToString(), wew[j].ToString());
}
}

Try this code in case both arrays are the same length
for (int i=0; i<wew.Length; i++)
{
Console.WriteLine(wow[i] + ", " + wew[i]);
}
If the length is different more logic is needed

Index was outside the bounds of the array confusion

I am trying to learn two dimensional array and I wrote some basic code, but I am getting this exception. Could you tell me what am I doing wrong?
static void Main(string[] args)
{
Random rnd = new Random();
int[,] array = new int[2, 2];
for (int i = 0; i < 2; i++)
{
for (int j = 0; j < 2; i++)
{
array[i, j] = rnd.Next(0, 100);
}
}
for (int i = 0; i < array.GetLength(0); i++)
{
Console.WriteLine(array[i, 0] + "---" + array[i, 1]);
}
Console.ReadLine();
}

The problem is in your inner for-loop. In the iterator section, you're incrementing the i variable, but it should be j. Try this:
for (int i = 0; i < 2; i++)
{
for (int j = 0; j < 2; j++)
{
array[i, j] = rnd.Next(0, 100);
}
}