Exercise $10\mathrm{.}3$

TASK: Write a switch$-$case statement below that implements the

state machine in "state$\_$machine$\_$tut$10.$png$".$

The switch statement should test the value of the variable

declared in Ex $10\mathrm{.}1$ and a case should be defined for every

state in the state machine $($every enumerator in the enum you

declared in Ex $10\mathrm{.}0).$

Use the $"$pb$\_$falling$\_$edge" variable from Ex $10\mathrm{.}2$ to trigger the

appropriate transitions between states.

Refer to lecture video $04-$ State Machine Implementation

from Week $10$

switch$-$case statement

A switch$-$case statement is an alterative to using a large number of if$-$then$-$else

statements when we want to perform different operations depending on the

value of some variable or expression. It has the syntax:

The break and default keywords are optional

break causes the switch statement to terminate.

If break is not included after a case, execution

will fall through to the next case.

If expression does not match any case, the

statements following default will be executed.

State machines: best practice

Plan your state machine before you start writing any code; draw a diagram.

Always use meaningful names for your states $($not STATE$0,$ STATE$1...)$

Check your state machine is complete; for every transition out of a state, there

should be exactly one branch of an in$-$then$-$else statement implemented in the

corresponding case.

Make sure the default case is handled; even if it should not be possible for your

state variable to take on an invalid value under normal operation.