Thread: using constructor & destructor

The following code compiles but will not link because the member functions of the two derived classes are missing. I need to implement the missing functions. But I haven't a clue! Any help in the right direction would be appreciated!

Code:

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>

class Employee							//class declaration
{
public:
	Employee (void);					//constructor
	~Employee (void);					//destructor

	void SetName (const char a_szfirst[],	//'mutator'
		          const char a_szlast[] );

	void GetName (char       a_szname[],	//'accessor'
		          const int  a_buflen );

	virtual float GetDollarsPerWeek (void)	//'accessor'
	{
	return 0;
	};

private:
	char *m_pFirstName;						//data members
	char *m_pLastName;
};


class HourlyEmployee : public Employee
{
public:
	HourlyEmployee (void);
	~HourlyEmployee (void);

	void SetAvgHoursPerWeek (const int a_hpw);
	void SetPayRate (const float a_dph);

	float GetDollarsPerWeek (void);		//avg 4 weeks per month

private:
	int m_AvgHoursPerWeek;
	float m_PayRate;
};


class SalaryEmployee : public Employee
{
public:
	SalaryEmployee (void);
	~SalaryEmployee (void);

	enum PayRatePeriod
		{
		eBiWeekly,
		eMonthly
		};

	void SetPayPeriod (enum PayRatePeriod a_prr);
	void SetPayRate (const float a_pr);

	float GetDollarsPerWeek (void);		//avg 4 weeks per month

private:
	enum PayRatePeriod m_PRR;
	float m_DollarsPerPeriod;
};

void main (void)
{
	const int NAMELEN = 60;
	char szname [NAMELEN+2] = {0};

	HourlyEmployee oHomer;

	oHomer.SetName ("Homer", "Simpson");
	oHomer.SetAvgHoursPerWeek (40);
	oHomer.SetPayRate (10.0);

	oHomer.GetName (szname, NAMELEN);			//'access'

	printf ("%s averages %.2f per week\n", szname,   oHomer.GetDollarsPerWeek () );

	SalaryEmployee *pMarge = new SalaryEmployee;

	pMarge->SetName ("Marge", "Simpson");
	pMarge->SetPayPeriod (SalaryEmployee::eMonthly);
	pMarge->SetPayRate (7500.0);

	pMarge->GetName (szname, NAMELEN);			//'access'

	printf ("%s averages %.2f per week\n", szname, pMarge->GetDollarsPerWeek());
}

       Employee::Employee (void)					constructor implementation
		 :m_pFirstName(0),
		  m_PLastName(0);
{
}

Employee::~Employee (void)					//destructor implementation
{
	if (m_pFirstName !=0)
		{
		delete [] m_pFirstName, m_pFirstName = 0;
		}
	if (m_pLastName !=0)
		{
		delete [] m_pLastName, m_pLastName = 0;
		}
}

void Employee::SetName (const char a_szfirst[],		//'mutator' implementation
						const char a_szlast[] )
{
	if (a_szfirst !=0 && a_szfirst[0] !=0)
	{
		const int buflen=strlen (a_szfirst);
		m_pFirstName = new char [buflen+2];
		memset (m_pFirstName, 0, (buflen+2));
		strcpy (m_pFirstName, a_szfirst);
	}

	if (a_szlast !=0 && a_szlast [0] !=0)
	{
		const int buflen = strlen (a_szlast);
		m_pLastName = new char [buflen+2];
		memset (m_pLastName, 0, (buflen+2));
		strcpy (m_pLastName, a_szlast);
	}
}

void Employee::GetName (char    a_szname[],			//'accessor' implementation
						const int a_buflen)
{
	if (0==m_pFirstName || 0==m_pLastName)
		return;
	int namelen = strlen(m_pFirstName) + 1 + strlen(m_pLastName);

	if (namelen > a_buflen)
		return;

	sprintf (a_szname, "%s %s", m_pFirstName, m_pLastName);
}
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