Delphi		repeat...until loop executes the code till the control condition is False. The following loop will execute until user will enter the 'exit' in the console input: repeat Readln(S); // some processing of S string until S='exit'; Important feature of repeat...until loop is checking the control condition after first iteration, so the loop code will execute at leat one time.
C#		do...while loop does exactly the same, but exits by the true in condition. do { s = Console.ReadLine(); // some processing of s string } while ( s != "exit" );      Do not forget to inverse condition.