Check out example codes for "how to add to an array c#". It will help you in understanding the concepts better.

Code Example 1

var Freds = new [] { "Fred", "Freddy" };
Freds = Freds.Concat(new [] { "Frederick" }).ToArray();

Code Example 2

List<int> add_list= new List<int>();
for (int i = 0; i < 400; i++)
{
   add_list.Add(value);
}

Code Example 3

// To add a value to a C# array, use 'Add()'
List<string> ls = new List<string>();
ls.Add("Hello");

Code Example 4

int[] arrayOfNumbers = new int[400];
for (int index = 0; runs < 400; runs++)
{
  	// Using array[index], you can modify the value at that index
    arrayOfNumbers[index] = value;
}

Code Example 5

List<int> termsList = new List<int>();
for (int runs = 0; runs < 400; runs++)
{
    termsList.Add(value);
}

// You can convert it back to an array if you would like to
int[] terms = termsList.ToArray();

Learn ReactJs, React Native from akashmittal.com