class3.cpp

Code

/*
 *   class3.cpp
 *   CIS 250
 *   David Klick
 *   2018-01-12
 *
 *   Demonstration usage of class with better practices.
 */

#include <cstring>
#include <iostream>
#include <iomanip>

/*
    Since no constructor is specified, a default constructor is 
    automatically created for this class. Likewise, a destructor,
    copy constructor, and assignment operator overload are also
    created automatically.
*/
class date {
public:
    int month;
    int day;
    int year;
};

class Employee {
private:
    // The following static variable will only have a single copy,
    // created when the class is loaded, and shared by all of the
    // objects of this class. It must be initialized outside of the
    // class declaration.
    static int count;

    // Each object gets a separate copy of each of the rest of these.
    char *lastname;   // This memory will be dynamically allocated
    unsigned long id;
    double rate;
    date hiredate;
    void init(const char* nm, unsigned long id, double rt, int y, int m, int d);
public:
    
    Employee();  // Default constructor
    Employee(const Employee& emp); // Copy constructor
    Employee(const char* nm, unsigned long id, double rt, int y, int m, int d);
    
    // Accessor methods
    static int getCount();
    unsigned long getId() const;
    double getRate() const;
    date getHireDate() const;
    
    // Mutator methods
    void setLastName(const char* nm);
    void setId(unsigned long id);
    void setRate(double rt);
    void setHireDate(date dt);
    void setHireDate(int y, int m, int d);
    
    // Assignment operator overload
    Employee operator=(const Employee& emp);

    // Destructor
    ~Employee();

    friend std::ostream& operator<<(std::ostream& strm, const Employee& emp);
};

// Initialization of static variable.
int Employee::count = 0;

void Employee::init(const char* nm, unsigned long id, double rt, int y, int m, int d) {
    lastname = NULL;
    setLastName(nm);
    this->id = id;  // this pointer needed because of variable name duplication
    setRate(rt);
    setHireDate(y, m, d);
    count++;
}

Employee::Employee() { 
    init("Unknown", 0, 0.0, 1970, 1, 1);
}

Employee::Employee(const Employee& emp) {
    init(emp.lastname, emp.id, emp.rate, emp.hiredate.year, emp.hiredate.month, emp.hiredate.day);
}

Employee::Employee(const char* nm, unsigned long id, double rt, int y, int m, int d) {
    init(nm, id, rt, y, m, d);
}

Employee Employee::operator=(const Employee& emp) {
    if (this == &emp) return *this;  // skip if assigning to self
    if (lastname != NULL) {
        delete[] lastname;
        lastname = NULL;
    }
    init(emp.lastname, emp.id, emp.rate, emp.hiredate.year, emp.hiredate.month, emp.hiredate.day);
    return *this;
}

void Employee::setLastName(const char* nm) {
    if (lastname != NULL) delete[] lastname;
    int len = strlen(nm);
    lastname = new char[len+1];
    if (lastname == NULL) {
        std::cout << "Error: Ran out of memory for name\n";
    } else {
        for (int i=0; i<len; i++) lastname[i] = nm[i];
        lastname[len] = '\0';
    }
}

void Employee::setId(unsigned long id) {
    this->id = id;
}

void Employee::setRate(double rt) {
    if (rt < 0.0) rate = 0.0;
    else rate = rt;
}

void Employee::setHireDate(date dt) {
    setHireDate(dt.year, dt.month, dt.day);
}

void Employee::setHireDate(int y, int m, int d) {
    hiredate.year = y;
    hiredate.month = m;
    hiredate.day = d;
}

int Employee::getCount() { return count; }

unsigned long Employee::getId() const { return id; }
double Employee::getRate() const { return rate; }
date Employee::getHireDate() const { return hiredate; }

Employee::~Employee() {
    if (lastname != NULL) {
        delete[] lastname;
        lastname = NULL;
    }
    count--;
}

std::ostream& operator<<(std::ostream& strm, const Employee& emp) {
    strm << std::setw(15) << emp.lastname << "  ID="
        << std::setfill('0') << std::setw(6) << emp.id << std::setfill(' ')
        << "  rate=$" << std::setw(6) << std::fixed << std::showpoint
        << std::setprecision(2) << emp.rate << "  hired=" << std::setw(2)
        << std::setfill('0') << emp.hiredate.month << "/" << std::setw(2)
        << emp.hiredate.day << '/' << std::setw(2)
        << (emp.hiredate.year % 100) << std::setfill(' ');
    return strm;
}


int main(void) {
    Employee emp[5] = {
        {"Smithson", 1786, 32.00, 1996, 3, 3},
        {"Guimond", 3654, 17.95, 2004, 4, 2},
        {"Crenshaw", 9812, 14.00, 2000, 11, 1},
        {"Lovitz", 17543, 27.25, 1999, 7, 10},
        {}};

    // use assignment operator
    emp[4] = emp[0];

    for (int i=0; i<5; i++) std::cout << emp[i] << std::endl;
    return 0;
}

/*
    Sample output:

       Smithson  ID=001786  rate=$ 32.00  hired=03/03/96
        Guimond  ID=003654  rate=$ 17.95  hired=04/02/04
       Crenshaw  ID=009812  rate=$ 14.00  hired=11/01/00
         Lovitz  ID=017543  rate=$ 27.25  hired=07/10/99
       Smithson  ID=001786  rate=$ 32.00  hired=03/03/96
*/