Lesson 6: while & do-while loops

Conditions gave us choice; loops give us repetition. while (condition) { ... } checks the condition before each round and runs the body again and again while it is true. For that you need a counter (like int i) that advances with i++ — otherwise the condition never turns off and the loop runs foreve

while is 'as long as you haven't arrived — take another step'. do-while is like tasting soup: you taste first (at least once!), and only then decide whether it needs more salt and taste again.

while (condition): Checks the condition before each round; the body runs while the condition is true.
do { } while (condition);: Checks the condition at the end, so the body runs at least once. Note the trailing semicolon!
counter & i++: A variable tracking the rounds; i++ adds 1 to it each time.
infinite loop: If the condition never becomes false (e.g. you forgot i++), the loop never stops.
input validation: Asking for input again and again until it is valid — the classic do-while use.