C＃使用Foreach循环以矩阵格式打印2D数组

Question

I am trying to create an array that will print out times tables. The first column is the 1 times table, the second is the 2 times table and so on. The user is asked for an input that will determine the number of rows and columns. I want to print the array in matrix format using a foreach loop. It works fine when I use a for loop but I would like to know how to achieve the same output using a foreach loop.

Shown is the code:

int rows;
int columns;

Console.WriteLine("Enter the number of rows");
rows = Convert.ToInt32(Console.ReadLine());

Console.WriteLine("Enter the number of columns");
columns = Convert.ToInt32(Console.ReadLine());

int[,] multiDim = new int[rows, columns];

for (int p = 0; p < multiDim.GetLength(0); p++)
{
    for (int k = 0; k < multiDim.GetLength(1); k++)
    {
       multiDim[p, k] = (p + 1) * (k + 1);
    }
    Console.WriteLine();
    Console.ReadLine();            
}

foreach (int i in multiDim)
    {
        Console.Write(i + " ");

        if (i == multiDim.GetLength(1))
        {
            Console.WriteLine();
        }
    }

    Console.ReadLine();

When I enter a value for rows that is above 2 the program does does not print the array in a proper array format. For example when I have 3 rows and 5 columns the output is:

1 2 3 4 5

2 4 6 8 10 3 6 9 12 15

I have read similar questions bu they do not seem to help. All help is appreciated.Thanks in advance.

Answer 1

Your code is looping over the values of the array, rather than the indexes. This means that it just happens to work initially since your values line up well.

I would suggest switching to using Jagged Arrays instead of Multidimensional arrays. This way you can do foreach (row in multiDim) , then foreach (cell in row)

If you still need to use a multidimensional array, then you need some form of counter which keeps track of the position of the array you are in. This is why a regular for loop is better to use for this scenario rather than a foreach loop.