In C #, yield return and yield break

Using system; using system. collections; public class list {public bool Onoff = false; public static ienumerable forexample () {yield return "1"; // execute yield return "2" during the first call "; // If (Onoff) executed in the second call // run {// run yield break for the third call, and then run the following statement yield break;} // otherwise, onoff is false yield return "3"; // execute yield return "4" when calling the fourth call; // execute it in the fifth call} static void main () {foreach (string s in forexample () console. writeline (s); console. readkey ();}}