c-resources/CPlusPlus20ForProgrammers-m.../examples/ch10/fig10_19-25/fig10_25.cpp

77 lines
3.3 KiB
C++

// fig10_25.cpp
// Processing Employee derived-class objects with variable-name handles
// then polymorphically using base-class pointers and references
#include <fmt/format.h>
#include <iostream>
#include <vector>
#include "Employee.h"
#include "SalariedEmployee.h"
#include "CommissionEmployee.h"
void virtualViaPointer(const Employee* baseClassPtr); // prototype
void virtualViaReference(const Employee& baseClassRef); // prototype
int main() {
// create derived-class objects
SalariedEmployee salaried{"John Smith", 800.0};
CommissionEmployee commission{"Sue Jones", 10000, .06};
// output each Employee
std::cout << "EMPLOYEES PROCESSED INDIVIDUALLY VIA VARIABLE NAMES\n"
<< fmt::format("{}\n{}{:.2f}\n\n{}\n{}{:.2f}\n\n",
salaried.toString(), "earned $", salaried.earnings(),
commission.toString(), "earned $", commission.earnings());
// create and initialize vector of base-class pointers
std::vector<Employee*> employees{&salaried, &commission};
std::cout << "EMPLOYEES PROCESSED POLYMORPHICALLY VIA"
<< " DYNAMIC BINDING\n\n";
// call virtualViaPointer to print each Employee
// and earnings using dynamic binding
std::cout << "VIRTUAL FUNCTION CALLS MADE VIA BASE-CLASS POINTERS\n";
for (const Employee* employeePtr : employees) {
virtualViaPointer(employeePtr);
}
// call virtualViaReference to print each Employee
// and earnings using dynamic binding
std::cout << "VIRTUAL FUNCTION CALLS MADE VIA BASE-CLASS REFERENCES\n";
for (const Employee* employeePtr : employees) {
virtualViaReference(*employeePtr); // note dereferenced pointer
}
}
// call Employee virtual functions toString and earnings via a
// base-class pointer using dynamic binding
void virtualViaPointer(const Employee* baseClassPtr) {
std::cout << fmt::format("{}\nearned ${:.2f}\n\n",
baseClassPtr->toString(), baseClassPtr->earnings());
}
// call Employee virtual functions toString and earnings via a
// base-class reference using dynamic binding
void virtualViaReference(const Employee& baseClassRef) {
std::cout << fmt::format("{}\nearned ${:.2f}\n\n",
baseClassRef.toString(), baseClassRef.earnings());
}
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