c# string concatenation

//Java
String firstName = "BarackObama";
String lastName = " Care";
//First way
System.out.println(firstName + lastName);
//Second way
String name = firstName + lastName;
System.out.println(name);
//Third way
System.out.println("BarackObama" + " Care");

string userName = "<Type your name here>";
string dateString = DateTime.Today.ToShortDateString();

// Use the + and += operators for one-time concatenations.
string str = "Hello " + userName + ". Today is " + dateString + ".";
System.Console.WriteLine(str);

str += " How are you today?";
System.Console.WriteLine(str);