Total number of elements in a specified dimension of an Array in C#

Array.GetLongLength(Int32) Method is used to get a 64-bit integer that represents the number of elements in the specified dimension of the Array.

Syntax:

public long GetLongLength (int dimension);

Here, dimension is the zero-based dimension of the Array whose length is to be calculated.

Return Value: It returns a 64-bit integer that represents the number of elements in the specified dimension.

Exception: This method throws IndexOutOfRangeException if the dimension is less than zero or greater than or equal to Rank.

Example:

// C# program to illustrate the
// Array.GetLongLength() method
using System;

namespace geeksforgeeks {

class GFG {

    // Main Method
    public static void Main()
    {

        // Three-dimensional array.
        int[,, ] arr = new int[,, ] {
                                      { { 1, 2, 3 },
                                        { 4, 5, 6 },
                                        { 6, 7, 8 }

                                      },

                                      { { 11, 12, 13 },
                                        { 14, 15, 16 },
                                        { 17, 18, 19 }
                                      },

                                      { { 21, 22, 23 },
                                        { 24, 25, 26 },
                                        { 27, 28, 29 }
                                      },
                                    };

        Console.Write("Total Number of Elements in"
                    + " first dimension of arr: ");

        // using GetLongLength Method
        Console.Write(arr.GetLongLength(0));

        // getting the type of returned value
        Console.WriteLine("\nType of returned Length: "
                        + (arr.GetLongLength(0)).GetType());

        // showing difference between GetLength
        // and GetLongLength method by getting
        // the type of the both method's
        // returned value

        Console.Write("\nTotal Number of Elements in "
                    + "second dimension of arr: ");

        // using GetLength Method
        Console.Write(arr.GetLength(1));

        // getting the type of returned value
        Console.WriteLine("\nType of returned Length: "
                        + (arr.GetLength(1)).GetType());

        Console.Write("\nTotal Number of Elements in "
                    + "second dimension of arr: ");

        // using GetLongLength() Method
        Console.Write(arr.GetLongLength(1));

        // getting the type of returned value
        Console.WriteLine("\nType of returned Length: "
                        + (arr.GetLongLength(1)).GetType());
    }
}
}

Output:

Total Number of Elements in first dimension of arr: 3
Type of returned Length: System.Int64

Total Number of Elements in second dimension of arr: 3
Type of returned Length: System.Int32

Total Number of Elements in second dimension of arr: 3
Type of returned Length: System.Int64

Note: In the above program, GetLength method return type is System.Int32 but the GetLongLength method return type is System.Int64.

Reference:

• https://docs.microsoft.com/en-us/dotnet/api/system.array.getlonglength?view=netframework-4.7.2