Explain dynamic model with its description.(C++)

A sample dynamic model of a real device shows how the various modeling constructs fit together. This is a model of a sears “Weekender” programmable thermostat. This device controls a furnace and their conditioner according to time dependent attributes which the owner enters using a pad of buttons.

While running, thermostat operates the furnace or air conditioner to keep the current temperature equal to the target temperature. The target temperature is taken from table of program values supplied by the user. The table specifies target temperature for 8 different time periods, 4 an weekdays and 4 on weekends, with start times specified by the user. The target temperature is reset from the table at the beginning of each program period. The user can override the target temperature for the reminder of the current period or indefinitely. The user programs the thermostat using a pad of 10 pushing buttons and 3 switches. The user sees parameters on an alphanumeric display. A switch illuminates a night light. The thermostat has a temperature sensor that  reads the air temperature. The thermostat  operates power relays for a furnace and an air conditioner, and an indicator lights up when the furnace and an air conditioner and an indicator lights up when the furnace or air conditioner is operating. Each push buttons generates an event every time it is pushed. We assigned one input event per button.

Temp up    raises target temperature or program temp

Temp down     raises target temperature or program temp   

Time fwd   advance clock time or program time.

Time Back        retards clock time of program time

Set clock    sets current time of day.

Set day       sets current day of the weeks.

Run Prgm  leaves setup or program mode and runs the program.

View Prgm  enters program mode to examine and modify program time and program temp settings.

Hold temp        holds current target temperature in spite of the program.

F.C. Button      alternates temperatures display between Fahrenheit and Celsius , each switch supplies a parameter value chosen from two or three possibilities. We model each switch as  independent concurrent sub diagram with one  state per switch setting. Although we assign events names to change in state, if is the state of each switch that is of interest. The switches and their setting are:

Light switch     light alphanumeric display values: light off, light on.

Season switch specifies which devices the thermostat controls. Values : heat,cool,off

Fan switch specifies when the ventilation fan operates values : fan on, fan auto

The thermostat controls the furnace, air conditions and fan power  relays. We model this controls by activities “run furnace”,”run air conditioner”, and run “fan” .