Delphi Programlama, The Until keyword ends a control loop that is always executed at least once, and which terminates when the Expression is satisfied (returns True). There is no need for Begin or End markers – the Repeat and Until keywords serve that purpose. It is used when it is important that the statements are at least executed once.

When your program needs to repeat a sequence of instructions you will need to use a loop.  There are three main types of loop in Delphi:

While Loop

A while loop checks a condition at the start of each iteration, and executes the enclosed statements only if the condition is met: