When we use exactly while loops

Answer 1

While loops are considered an "indefinite loop" (meaning, we don't know when they will end). Therefore, you use something called a "sentinal value" that the loop checks every iteration. The sentinel value is used to terminate the loop whenever it's necessary.

Answer 2

While loops are indefinite, meaning that we don't know when they will end. For loops are definite, meaning we do know when they will end.

Answer 3

what is deference between while loops and for loops?