Download Arduino-Based Dataloggers: Hardware and Software

while… and do… while loops
These
conditional
execution
constructs
allow a block of
statements
to
be
executed repetitively as
long
as
certain
conditions are met, as
opposed to for… loops,
in which the number of
executions is set ahead
of time. The statements
inside a while… loop
may not be executed at
all, depending on the
initial value of a Boolean
expression controlling
execution. do… while
loops
are
always
executed at least once
Sketch 5. Conditional execution loops.
because the comparison
with the Boolean expression is done at the end of the loop rather than at the beginning. It is possible to
write loops that will never terminate, and it is a programmer's responsibility to make sure this doesn't
happen.
In Sketch 5, the code waits for you to press a key and [Enter] in the serial port monitor. See 2.2.6
Math functions, below, for more information about using the random number generator. The output from
this sketch is always the same set of values between 1 and 100. These values are "random" in the sense
that they would pass statistical tests for randomness. Note that the loop terminates after seeing a value
≥50 because the test is done at the bottom of the loop.
switch construct
The switch construct controls execution based on matching a value with a list of integer or
character values. (It won't work with real numbers.) The case values in the list don't have to be in any
particular order. This construct is often more clear than using a lengthy if… else if… statement.
However, unlike if… statements, which execute only the first true branch, each case in the switch
construct requires a break; statement to exit when the first match with int value or variable is
found; without a break; all the other remaining operations will also be executed. The default
keyword provides the opportunity for responding to not finding a match. Often, this response might be to
display a message explaining that no match was found.
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