Demonstrate Polymorphism, virtual functions and dynamic binding. - C++ Class

C++ examples for Class:Polymorphism

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Description

Demonstrate Polymorphism, virtual functions and dynamic binding. 

#include <string>
using namespace std;

class Employee {
 public:
    Employee(const std::string&, const std::string&,
                       const std::string&, double, double);

    void setFirstName(const std::string&);
    std::string getFirstName() const;

    void setLastName(const std::string&);
    std::string getLastName() const;

    void setSocialSecurityNumber(const std::string&);
    std::string getSocialSecurityNumber() const;

    void setGrossSales(double);
    double getGrossSales();

    void setCommissionRate(double);
    double getCommissionRate() const;

    virtual double earnings() const;
    virtual void print() const;

 private:
    std::string firstName;
    std::string lastName;
    std::string socialSecurityNumber;
    double grossSales;
    double commissionRate;
};



class BasePlusEmployee : public Employee {
 public:
    BasePlusEmployee(const std::string&,
                               const std::string&, const std::string&,
                               double = 0.0f, double = 0.0f, double = 0.0f);

    void setBaseSalary(double);
    double getBaseSalary() const;

    virtual double earnings() const;
    virtual void print() const;

 private:
    double baseSalary;
};


#include <iomanip>
#include <iostream>

int main(int argc, const char *argv[]) {
    // create base-class object
    Employee commissionEmployee("Sue", "Jones", "222-22-2222", 10000,.06);

    // create base-class pointer
    Employee *commissionEmployeePtr = 0;

    // create derived-class object
    BasePlusEmployee basePlusEmployee("Bob", "Lewis", "333-33-3333", 5000, .04, 300);

    // create dervied-class pointer
    BasePlusEmployee *basePlusEmployeePtr = 0;

    // set floating-point output formatting
    std::cout << std::fixed << std::setprecision(2);

    // output objects using static binding
    std::cout << "Invoking print function on base-class and derived-class "
              << "\nobject with static binding\n\n";
    commissionEmployee.print();  // static binding
    std::cout << "\n\n";
    basePlusEmployee.print();  // static binding

    // output objects with dynamic binding
    std::cout << "\n\n\nInvoking print function on base-class and "
              << "derived-class \nobjects with dynamic binding";

    // aim base-class pointer at base-class object and print
    commissionEmployeePtr = &commissionEmployee;
    std::cout << "\n\nCalling virtual function print with derived-class "
              << "pointer\nto derived-class object invokes derived-class "
              << "print function:\n\n";
    basePlusEmployeePtr->print();

    // aim base-class pointer at derived-class object and print
    commissionEmployeePtr = &basePlusEmployee;
    std::cout << "\n\nCalling virtual function print with base-class pointer"
              << "\nto derived-class object invokes derived-class "
              << "print function:\n\n";

    // polymorphism; invokes BasePlusEmployee's print;
    // base-class pointer to derived-class object
    commissionEmployeePtr->print();

    std::cout << std::endl;

    return 0;
}

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