return; will exit a method in C#.
See code snippet below
using System;
namespace Exercise_strings
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Input string separated by -");
var stringInput = Console.ReadLine();
if (string.IsNullOrWhiteSpace(stringInput))
{
Console.WriteLine("Nothing entered");
return;
}
}
So in this case if a user enters a null string or whitespace, the use of the return method terminates the Main method elegantly.