**Repetition/Looping Structures**

Another collection of the most
fundamental structures has to do with repeating operations. This
is done in two fundamentally different ways, incrementing a
counter and evaluating a criteria. Obviously you could use a
criteria that makes use of counting so the approaches aren't mutually
exclusive. It is also possible to evaluate the criteria either at
the beginning or the end of the loop.
For example, you want to loop through and consider the grades of all the students in a class. You may be computing each person's overall class average. There are endless examples of such situations. The following three diagrams represent the three fundamental repetition/looping structures. The first one is the basic |

The next structure relates to having
evaluating the condition at the end of the loop. This is enacted
with a do - while
loop in Java. |

Finally, we have highly structured
situations where the number of repetitions through the loop is largely
foreknowledge. This is equivalent to a for
loop in Java. |