hi i am trying to make a function for calculating the commercial boat fee, so if a boat is commercial, the program will add additional fee to the total sum, and if its not it won't add anything to it. i got the function to run, but all i am getting are some really random numbers like 9329030283049283094823 and i don't know how to fix it. Look at the Sailboat::Calcfee and Powerboat::Calcfee function, i think that's where the problem at, or maybe not. buttomline, i DONNO ~_~. this is my first year of doing C++, anyway. Here is my code:

#include <iostream>
#include <string>
#include <cctype>
#include <typeinfo>
using namespace std;

class Boatyard
{
protected:
	double length;
	double beam;
	double draft;
	string name;
	int material;
	int manufacture;
	bool commercial;
	const static char CH=20;
	
	static double L_MAX;
	static double L_MIN;
	static double B_MAX;
	static double B_MIN;
	static double D_MAX;
	static double D_MIN;
	static int M_MAX;
	static int M_MIN;
	static int MA_MAX;
	static int MA_MIN;

public:
	

	string	Key();
	bool Commercial();
	void Commercial(bool _z);
	double	Length();
	void	Length(double _z);
	double	Beam();
	void	Beam(double _z);
	double	Draft();
	void	Draft(double _z);
	string	Name();
	void	Name(string _z);
	int		Material();
	void    Material(int _z);
	int		Manufacture();
	void 	Manufacture(int _z);
	virtual void Calcfee(double _z)=0;
	virtual void show()=0;
	
	Boatyard();
	Boatyard(double _len, double _bea, double _dra, string _bnam, int _mat, int _manuf, bool _com);
	Boatyard(const Boatyard &_b);
	
	double _validateLBD(double _z, const double MAX, const double MIN);
	int Boatyard::_validateMAMAN(int _z, const int MAX, const int MIN);


}; // end declaration
class	Sailboat : public Boatyard
{
protected: 

		int rig;
		int hull;
		double sailfee;
		static int MAX_RIG;
		static int MIN_RIG;
		static int MAX_HULL;
		static int MIN_HULL;
	

public:

		int Rig();
		void Rig(int _z);
		int Hull();
		void Hull(int _z);

		double Calcfee();
        void Calcfee(double _z);
		void show();

		Sailboat();
		Sailboat(double _len, double _bea, double _dra, string _bnam, int _mat, int _manuf, bool _com, int _ri, int _hul);
		Sailboat(const Sailboat & _s);
		int _validation(int _z, const int MAX, const int MIN);
		
};//end of sailboat class

class Powerboat : public Boatyard
{
protected:

	int hp;
	int fuel;
	double powerfee;
	static int MAX_HP;
	static int MIN_HP;
	static int MAX_FUEL;
	static int MIN_FUEL;


public:

	int Hp();
	void Hp(int _z);
	int Fuel();
	void Fuel(int _z);

	double Calcfee();
	void  Calcfee(double _v);
	void  show();

	Powerboat();
	Powerboat(double _len, double _bea, double _dra, string _bnam, int _mat, int _manuf, bool _com, int _hp, int _fue);
	Powerboat(const Powerboat & _p);
	int _validationz(int _z, const int MAX, const int MIN);
};//end of powerboat class
	double Boatyard::Length(){return length;}
	void Boatyard::Length(double _z)
	{
		length = _validateLBD(length, L_MAX, L_MIN);
	}
	double Boatyard::Beam(){return beam;}
	void Boatyard::Beam(double _z)
	{
		beam = _validateLBD(beam, B_MAX, B_MIN);
	}
	double Boatyard::Draft(){return draft;}
	void Boatyard::Draft(double _z)
	{	
		draft = _validateLBD(draft, D_MAX, D_MIN);
	}
	string Boatyard::Key(){return name;}
	string Boatyard::Name(){return name;}
	void Boatyard::Name(string _z)
	{
		if(_z.length()<=CH)
		{
			name = _z;
		}
		else
			name= _z.substr(0,CH);
		
	}
	bool Boatyard::Commercial(){return commercial;}
	void Boatyard::Commercial(bool _z)
	{
		commercial = _z;
	}
	int Boatyard::Material(){return material;}
	void Boatyard::Material(int _z)
	{
		material = _validateMAMAN(material, M_MAX, M_MIN);
	}
	int Boatyard::Manufacture(){return manufacture;}
	void Boatyard::Manufacture(int _z)
	{
		manufacture = _validateMAMAN(manufacture, MA_MAX, MA_MIN);
	}
	Boatyard::Boatyard() : length(),beam(),draft(),name(),material(),manufacture(),commercial()
{
}
Boatyard::Boatyard(double _len, double _bea, double _dra, string _bnam, int _mat, int _manuf, bool _com):length(_len), beam(_bea), draft(_dra), name(_bnam), material(_mat), manufacture(_manuf), commercial(_com)
{
	Length(length);
	Beam(beam);
	Draft(draft);
	Name(name);
	Material(material);
	Manufacture(manufacture);
}
Boatyard::Boatyard(const Boatyard &_b){};

void Boatyard::show()
{
	cout.setf(ios::fixed);
	cout.setf(ios::showpoint);
	cout.precision(1);
	cout << "Length:" << length << " Meter " << "Beam:" << beam << " Meter " <<"Draft: " <<  draft <<" Meter " << endl << "Person's Name: "<< name << " Material: " << material << " Manufacture: " << manufacture << endl;
}
//end of implementation for Boatyard

int		Sailboat::Rig(){return rig;}
void	Sailboat::Rig(int _z)
{
	rig = _validation(rig,MAX_RIG,MIN_RIG);
}
int		Sailboat::Hull(){return hull;}
void    Sailboat::Hull(int _z)
{
	hull = _validation(hull, MAX_HULL, MIN_HULL);
}
double Sailboat::Calcfee(){return sailfee;}
void Sailboat::Calcfee(double _z)
{
	double LOA = length;

	if (commercial = false)
	{
		_z = LOA*50;
	}
	if (commercial = true)
	{
		_z = LOA*50+7.5;
	}

}
Sailboat::Sailboat() :Boatyard(), rig (), hull (){};
Sailboat::Sailboat(double _len, double _bea, double _dra, string _bnam, int _mat, int _manuf, bool _com, int _ri, int _hul ) : Boatyard( _len,  _bea,  _dra,  _bnam,  _mat,  _manuf, _com),rig(_ri),hull(_hul){};
Sailboat::Sailboat(const Sailboat &_s):Boatyard(_s),rig( _s.rig),hull( _s.hull){};
void Sailboat::show()
{
	cout.setf(ios::fixed);
	cout.setf(ios::showpoint);
	cout.precision(1);
	cout << "Sailboat" << endl << "Length:" << this->length << " Meter " << "Beam:" << this->beam << " Meter " <<"Draft: " <<  this->draft <<" Meter " << endl << "Person's Name: "<< this->name << " Material: " << this->material << " Manufacture: " << this->manufacture << "Sailboat Fee: " << this->sailfee << " $ " << " Rig:" << this-> rig << " Hull: " << this->hull << endl;	
}
int Powerboat::Hp(){return hp;}
void Powerboat::Hp(int _z)
{
	hp = _validationz(hp,MAX_HP,MIN_HP);
}
int Powerboat::Fuel(){return fuel;}
void Powerboat::Fuel(int _z)
{
    fuel = _validationz(fuel,MAX_FUEL,MIN_FUEL);
}
double Powerboat::Calcfee(){return powerfee;}
void  Powerboat::Calcfee(double _z)
{
	if(commercial = false)
	{
		if(hp < 150)
		{
			_z = ((length*50)+100)+7.5;
		}
		if((hp >150)&&(hp < 301))
		{
			_z = ((length*50)+150)+7.5;
		}
		if(hp > 300)
		{
			_z = ((length*50)+200)+7.5;
		}
	}
	if(commercial = true)
	{
		if(hp < 150)
		{
			_z = ((length*50)+100);
		}
		if((hp >150)&&(hp < 301))
		{
			_z = ((length*50)+150);
		}
		if(hp > 300)
		{
			_z = ((length*50)+200);
		}
	}
}
Powerboat::Powerboat() :Boatyard(), hp(), fuel(){};
Powerboat::Powerboat(double _len, double _bea, double _dra, string _bnam, int _mat, int _manuf, bool _com, int _hp, int _fue) :Boatyard( _len,  _bea,  _dra,  _bnam,  _mat, _manuf, _com),hp( _hp),fuel( _fue){};
Powerboat::Powerboat(const Powerboat &_p):Boatyard(_p),hp(_p.hp),fuel(_p.fuel){};

void Powerboat::show()
{
	cout.setf(ios::fixed);
	cout.setf(ios::showpoint);
	cout.precision(1);
	cout << "Powerboat" << endl << "Length:" << this->length << " Meter " << "Beam:" << this->beam << " Meter " <<"Draft: " <<  this->draft <<" Meter " << endl << "Person's Name: "<< this->name << " Material: " << this->material << " Manufacture: " << this->manufacture << "Powerboat Fee: " << this->powerfee << " $" << "HorsePower" << this->hp << "Fuel Type: " << this->fuel << endl;	
}
double Boatyard::_validateLBD(double _z, const double MAX, const double MIN)
{
	if(_z > MAX)
	{
		return -1;
	}
	if(_z < MIN)
	{
		return -1;
	}
	return _z;
}
int Boatyard::_validateMAMAN(int _z, const int MAX, const int MIN)
{
	if(_z > MAX)
	{
		return 0;
	}
	if(_z < MIN)
	{
		return 0;
	}
	return _z;
}
int Powerboat::_validationz(int _z, const int MAX, const int MIN)
{
if(_z < MIN)
{
	return -1;
}
if(_z > MAX)
{
	return -1;
}
return _z;
}
int Sailboat::_validation(int _z, const int MAX, const int MIN)
{
	if(_z > MAX)
	{
		return 0;
	}
	if(_z < MIN)
	{
		return 0;
	}
	return _z;
}
int Powerboat::MAX_HP = 400;
int Powerboat::MIN_HP = 0;
int Powerboat::MAX_FUEL = 3;
int Powerboat::MIN_FUEL = 1;
int Sailboat::MAX_RIG = 2;
int Sailboat::MIN_RIG = 1;
int Sailboat::MAX_HULL = 2;
int Sailboat::MIN_HULL = 1;
double Boatyard::L_MAX = 10;
double Boatyard::L_MIN = 3;
double Boatyard::B_MAX = 3;
double Boatyard::B_MIN = 1;
double Boatyard::D_MAX = 2;
double Boatyard::D_MIN = .25;
int	   Boatyard::M_MAX = 4; 
int	   Boatyard::M_MIN = 1;
int    Boatyard::MA_MAX = 3;
int    Boatyard::MA_MIN = 1;

void Printthem(Boatyard * _obj);

void main()
{
	Sailboat a(3,1,2,"BIGCANNON",2,1,true,1,2);
	a.show();
}

void printthem(Boatyard * _obj)
{
	Boatyard * _b = dynamic_cast<Boatyard *> (_obj);
	Sailboat * _s = dynamic_cast<Sailboat *> (_obj);
	Powerboat * _p = dynamic_cast<Powerboat *> (_obj);
}
void Sailboat::Calcfee(double _z)
{
	double LOA = length;

	if (commercial = false)
	{
		_z = LOA*50;
	}
	if (commercial = true)
	{
		_z = LOA*50+7.5;
	}

}

This function doesn't do anything, and it still does it wrong.
Use == for comparison, not =

In fact for boolean, variables, you should have if ( ! commercial ) and if ( commercial ) respectively.

It would be better still as if ( ! commercial ) { ... } else { ... } The next problem with it is that all it does is modify local variables. Anything it does is lost when the function returns, so all in all, it just wastes a bit of time.

Your other calcfree() seems equally useless at changing the program state.

Oh, and your use of void main
http://c-faq.com/ansi/maindecl.html
http://www.research.att.com/~bs/bs_faq2.html#void-main

ok it helped to an extent, but now its displaying even more numbers than it did before ... =.=.

double Powerboat::Calcfee(){return powerfee;}
void  Powerboat::Calcfee(double _z)
{
	if(!commercial)
	{
		if(hp < 150)
		{
			powerfee = ((length*50)+100)+7.5;
		}
		else if((hp >149)&&(hp < 301))
		{
			powerfee = ((length*50)+150)+7.5;
		}
		else
		{
			powerfee = ((length*50)+200)+7.5;
		}
	}
	if(commercial)
	{
		if(hp < 150)
		{
			powerfee = ((length*50)+100);
		}
		else if((hp >150)&&(hp < 301))
		{
			powerfee = ((length*50)+150);
		}
		else
		{
			powerfee = ((length*50)+200);
		}
	}
}
double Sailboat::Calcfee(){return sailfee;}
void Sailboat::Calcfee(double _z)
{

	if (!commercial)
	{
		sailfee = length*50;
	}
	if (commercial)
	{
		sailfee = length*50+7.5;
	}

}

I don't know how to use a debugger... none of my C++ teacher tell me how to use it...

You build the project for debug.

You then right-click on the first line of main and then select "insert breakpoint". Try clicking in the margin if that doesn't work.

You then execute the program / or run with debug (again, look carefully through the menus).

When the program runs, it will stop at the breakpoint.

Set other breakpoints to where you think interesting stuff is going to happen.

You can examine any variable in scope, often by simply pointing at it. You can also add variables to a "watch" window to observe changes as they happen.

You can then execute the program using "Step", "Step Into" and "Step Over" to control how much of the program is run before it stops to let you have another look around.

When the program starts doing something you didn't expect, you've found a bug.
Fix it, compile and repeat until you have a "bug free" program.

Or add output statements to display values as the program runs with the location within the program.

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