Итерация по сложным структурам

int[][] matrix = new int[3][];
matrix[0] = new int[] { 1, 2, 3 };
matrix[1] = new int[] { 4, 5, 6 };
matrix[2] = new int[] { 7, 8, 9 };

for (int i = 0; i < matrix.Length; i++)
{
    for (int j = 0; j < matrix[i].Length; j++)
    {
        Console.WriteLine(matrix[i][j]);
    }
}

string[] words = { "hello", "world" };

for (int i = 0; i < words.Length; i++)
{
    for (int j = 0; j < words[i].Length; j++)
    {
        Console.WriteLine(words[i][j]);
    }
}

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

int totalItems = 0;
for (int i = 0; i < jaggedArray.Length; i++)
{
    totalItems += jaggedArray[i].Length;
}
Console.WriteLine($"Total items: {totalItems}");