Read numbers from the console given in a single line, separated by a space

You can use String.Split. You can provide the character(s) that you want to use to split the string into multiple. If you provide none all white-spaces are assumed as split-characters(so new-line, tab etc):

string[] tokens = line.Split(); // all spaces, tab- and newline characters are used

or, if you want to use only spaces as delimiter:

string[] tokens = line.Split(' ');

If you want to parse them to int you can use Array.ConvertAll():

int[] numbers = Array.ConvertAll(tokens, int.Parse); // fails if the format is invalid

If you want to check if the format is valid use int.TryParse.

You can use Linq to read the line then split and finally convert each item to integers:

  int[] numbers = Console
        .ReadLine()
        .Split(new Char[] {' '}, StringSplitOptions.RemoveEmptyEntries)
        .Select(item => int.Parse(item))
        .ToArray();

You can split the line using String.Split():

var line = Console.ReadLine();
var numbers = line.Split(' ');
foreach(var number in numbers)
{
    int num;
    if (Int32.TryParse(number, out num))
    {
        // num is your number as integer
    }
}