help creating a class

I am trying to creat a gaspump class. I need to creat the functions, reset fuel pump, reset fuel charge, display fuel charges, display fuel pumped, pump status ( on or off), fuel grade( leaded, unleaded, or diesel), and octane ratings. I am unsure of how to write the functions. I took a stab at it. I also wanted to know about reating objects. Should they be pump1, pump2 etc.. or the cars that use the pumps like Nissan, volvo, etc... Any help would anyone could give would ease my stress greatly. Here is the class that I created:

Code:

---


class  gaspump
{
    private:
        void    ResetFuelCharges(int bills, int coins);
        void    ResetFuelPumped(int gal);
        float  gallons;
        float  dollars;
        float  cents;


    public:
        float    DisplayFuelCharge(char grade, int octane, int gal, float charges);
        float    DisplayFuelPumped;
        bool    PumpStatus;
        char    FuelGrades;
        int      OctaneRatings;
       
};

and the functions that I done so far:

void gaspump::ResetFuelCharges(float bills, float coins)
    {
        dollars = 0.00;
        cents = .00;
    }
   
void gaspump::ResetFuelPumped(float gals)
    {
        gallons = gal;
        gallons = 0.00;
    }
   
float gaspump::DisplayFuelCharges(char grade, int octane, int gal, float charges)
    {
        if (grade ++ "L") 
        {
          charges = 2.00 * gallons;
          return charges;
        }
          if (grade =="D")
          {
              charges = 2.25 * gallons;
              return charges;
          }
              if (grade == "U") && (octane == "R")
              {
                charges = 1.40 * gallons;
                return charges;
              }
                if (grade =="U") && (octane == "S")
                {
                    charges = 1.50 * gallons;
                    return charges;
                }
                else
                    if (grade == "U") && (octane == "G")
                    {
                        charges = 1.75 * gallons;
                        return charges;
                    }
}

---

Couple of problems I can see right away.

Code:

---


class  gaspump
{
    private:
        void    ResetFuelCharges(int bills, int coins);
        void    ResetFuelPumped(int gal);
        float  gallons;
        float  dollars;
        float  cents;


    public:
        float    DisplayFuelCharge(char grade, int octane, int gal, float charges);
        float    DisplayFuelPumped;
        bool    PumpStatus;
        char    FuelGrades;
        int      OctaneRatings;
       
};

and the functions that I done so far:

void gaspump::ResetFuelCharges(float bills, float coins) // why have paramaters if you're not going to use them?
    {
        dollars = 0.00;
        cents = .00;
    }
   
void gaspump::ResetFuelPumped(float gals)
    {
        gallons = gal;  // huh?  why have this line?
        gallons = 0.00;
    }
   
float gaspump::DisplayFuelCharges(char grade, int octane, int gal, float charges)
    {
        if (grade ++ "L")  // I think this typo is pretty obvious
        {
          charges = 2.00 * gallons;
          return charges;
        }
          if (grade =="D")
          {
              charges = 2.25 * gallons;
              return charges;
          }
              if (grade == "U") && (octane == "R")
              {
                charges = 1.40 * gallons;
                return charges;
              }
                if (grade =="U") && (octane == "S")
                {
                    charges = 1.50 * gallons;
                    return charges;
                }
                else
                    if (grade == "U") && (octane == "G")
                    {
                        charges = 1.75 * gallons;
                        return charges;
                    }
}

---

Advice: Keep everything private unless it "has" to be public, particularly data members. That way the class has greater control over what can happen to it.