Thermostat

Design the control logic for a heating/cooling thermostat with a fan:

• In heating mode (mode = 1), turn on the heater when it is too cold (too_cold = 1). Never use the air conditioner in this mode.
• In cooling mode (mode = 0), turn on the air conditioner aircon when it is too hot (too_hot = 1). Never use the heater in this mode.
• The fan must run whenever the heater or the air conditioner is on, and also whenever the user requests it directly with fan_on = 1.