string str1 = "I love programming and coding";
string str2 = "Technology is changing the world";
string str3 = "Coding is a skill worth mastering";

string newStr = str1 + " " + str2;

List words = new List();
words.AddRange(newStr.Split(' '));

words.Sort();

foreach (string word in words)
{
Console.Write(word + " ");
}
Console.ReadLine();