using System; using System.Text.RegularExpressions; namespace RegExApplication { class Program { static void Main(string[] args) { string input = "Hello World "; string pattern = "\\s+"; string replacement = " "; Regex rgx = new Regex(pattern); string result = rgx.Replace(input, replacement); Console.WriteLine("Original String: {0}", input); Console.WriteLine("Replacement String: {0}", result); Console.ReadKey(); } } }