Classes & Constructors Question: What am I missing?

[blairtch]

Write a full class definition for a class named GasTank , and containing the following members:
A data member named amount of type double .
A constructor that no parameters . The constructor initializes the data member amount to 0.
A function named addGas that accepts a parameter of type double . The value of the amount instance variable is increased by the value of the parameter .
A function named useGas that accepts a parameter of type double . The value of the amount data member is decreased by the value of the parameter .
A function named getGasLevel that accepts no parameters . getGasLevel returns the value of the amount data member.


I keep getting errors telling me my prototypes don't match any in the class. Not sure what I'm missing. Any help or advice would be appreciated.

Here is my code:

class GasTank
{
   private: 
	double amount;
	
   public: 
	GasTank();
	
    void addGas(double);
	void useGas(double);
	double getGasLevel();
	
};

double GasTank::addGas(double g)  
{
	amount = amount + g;
}

double GasTank::useGas(double g)  
{
	amount = amount - g;
}

GasTank::getGasLevel()  
{
	return amount;
}

[Zhuge]

It is actually being very specific; your actual definitions don't match the prototypes in the class.

On line 9, you declare addGas() as returning void, but on line 15 you have it return a double.

On line 10, you declare useGas() as returning void, but on line 20 you have it return a double.

On line 11 you declare getGasLevel() as returning a double, but on line 25 you haven't even specified a return value.

[blairtch]

Very helpful thank you!

I am still get an error:

class GasTank
{
   private: 
	double amount;
	
   public: 
	GasTank();
	
    void addGas(double);
	void useGas(double);
	double getGasLevel();
	
};

void GasTank::addGas(double g)  
{
	amount += g;
}

void GasTank::useGas(double g)  
{
	amount -= g;
}

double GasTank::getGasLevel()  
{
	return amount;
}

[shadowCODE]

Your not missing anything in the piece of code. If you still get an error, its not here

[Zhuge]

It would be useful also if you would tell us what the error is. ;)

[AbstractionAnon]

You declare a default constructor on line 7, but you do not appear to have an implementation for it. Your implementation is required to set amount to zero per the instructions:
A constructor that no parameters . The constructor initializes the data member amount to 0.