Correction: The Right Way To Manage State in C++

television-buggy.cpp

void Television::pressPowerButton() 
{
    tvIsOn = !tvIsOn;

    if (tvIsOn == true) 
    {
        turnOn();
    } 
    else
    {
        turnOff();
    }
}

television-buggy.h

class Television
{
public:
    Television();
    ~Television();

    void pressPowerButton();

private:
   bool tvIsOn; //state variable

   void turnOn();
   void turnOff();
};

television.cpp

Television::Television() 
{   
        //on creation, the television is off.
    tvIsOn = false;
}

Television::~Television()
{
    
}

bool Television::pressPowerButton() 
{
        //if the current state is on, try to turn off
    if (tvIsOn == true) 
    {
        tvIsOn = turnOff();
    }
        //otherwise, the current state is off, so try to turn on
    else
    {
        tvIsOn = turnOn();
    }
    
        //report the current state back to the user
    return tvIsOn;
}

bool Television::turnOn() 
{
        //set a variable for success
    bool success = false;
    
    //do stuff to turn on, set success variable accordingly.
    
    //if we succeeded, return the new state of "on".
    if (success)
    {
        return true;
    }
        //otherwise, keep the state as "off".
    else
    {
        return false;
    }
}

bool Television::turnOff() 
{
        //set a variable for success
    bool success = false;
    
        //do stuff to turn off, set success variable
    
        //if we succeeded, return the new state of "off".
    if (success)
    {
        return false;
    }
        //otherwise, keep the state as "on".
    else
    {
        return true;
    }
}

television.h

class Television
{
public:
    Television();
    ~Television();

    bool pressPowerButton();

private:
   bool tvIsOn; //state variable

   bool turnOn();
   bool turnOff();
};

usage.cpp

Television * tv = new Television();

//conditional is true if call to pressPowerButton() is false.
if ( !( tv->pressPowerButton() ) ) {
    //alert! We have an issue
}

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