C# 0 The Complete Reference

PART I

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PART IPART I

The output is shown here:

Length of nums is 300

As the output verifies, 

Length

 obtains the number of elements that 

nums

 can hold, which 

is 300 (10×5×6) in this case. It is not possible to use 

Length

 to obtain the length of a specific 

dimension.

The inclusion of the 

Length

 property simplifies many algorithms by making certain 

types of array operations easier—and safer—to perform. For example, the following 

program uses 

Length

 to reverse the contents of an array by copying it back-to-front into 

another array:

// Reverse an array.

using System;

class RevCopy {

  static void Main() {

    int i,j;

    int[] nums1 = new int[10];

    int[] nums2 = new int[10];

    for(i=0; i < nums1.Length; i++) nums1[i] = i;

    Console.Write("Original contents: ");

    for(i=0; i < nums2.Length; i++)

      Console.Write(nums1[i] + " ");

    Console.WriteLine();

    // Reverse copy nums1 to nums2.

    if(nums2.Length >= nums1.Length) // make sure nums2 is long enough

      for(i=0, j=nums1.Length-1; i < nums1.Length; i++, j--)

        nums2[j] = nums1[i];

    Console.Write("Reversed contents: ");

    for(i=0; i < nums2.Length; i++)

      Console.Write(nums2[i] + " ");

    Console.WriteLine();

  }

}

Here is the output:

Original contents: 0 1 2 3 4 5 6 7 8 9

Reversed contents: 9 8 7 6 5 4 3 2 1 0

Here, 

Length

 helps perform two important functions. First, it is used to confirm that the 

target array is large enough to hold the contents of the source array. Second, it provides 

the termination condition of the 

for

 loop that performs the reverse copy. Of course, in this 

simple example, the size of the arrays is easily known, but this same approach can be 

applied to a wide range of more challenging situations.

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