Iteration (loops)

Iteration repeats a block of code. Choose the loop that matches whether you know the number of repetitions in advance.

• `for i := 1 to n do` — a KNOWN, fixed number of repetitions (a counter loop).
• `while condition do` — repeat while a condition holds; tests BEFORE each pass (may run zero times).
• `repeat … until condition` — tests AFTER each pass, so it always runs at least once.
• Guard against infinite loops: something inside a while/repeat must eventually make the condition stop.

• Loop / iteration — repeating a block of statements.
• Counter — a variable that counts the passes of a loop.
• Infinite loop — a loop whose stop condition is never met.