Uses a loop control variable to count upwards or downwards (usually by an integer increment.)
Loop keeps going until a special value is encountered in the data.
Loop keeps going until a test determines that the desired result has been achieved.
Each type of loop can be built using the
along with other statements.
are three things
(in each of the three types of loops)
that must be done correctly:
Overlooking one of these aspects results in a defective loop. But usually each of these aspects is found in a different place in a program. No wonder that loops often go wrong!
The flow chart to the right shows what all loops must do.
It could be for any of the three types of loops.
Would it be convenient to have all three aspects combined into one statement?