In-Class Exercise
Member Operators
This exercise overloads
an operator to enable client programs to use objects as
operands in expressions.
Given Information
Consider the main program shown on the
left and the output shown on the right
Client Module
// Employee
// main.cpp
#include <iostream>
using namespace std;
#include "Employee.h"
int main() {
Employee null,
mark(3456, "Mark"),
rose(3457, "Rose", 10.70);
null.display();
cout << endl;
mark.display();
cout << endl;
rose.display();
cout << endl;
}
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no data available
Mark (3456) $10.25
Rose (3457) $10.70
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Employee Module
Employee.h
// Employee - Header File
// Employee.h
const double MIN_WAGE = 10.25;
const int MAX_NAME = 20;
class Employee {
int no;
char name[MAX_NAME + 1];
double rate;
public:
Employee();
Employee(int, const char*);
Employee(int, const char*, double);
void display() const;
};
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Employee.cpp
// Employee - Implementation File
// Employee.cpp
#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;
#include "Employee.h"
Employee::Employee() {
// safe empty state
no = 0;
name[0] = '\0';
rate = MIN_WAGE;
}
Employee::Employee(int n, const char* nm) {
Employee temp(n, nm, MIN_WAGE)
*this = temp;
}
Employee::Employee(int n, const char* nm, double w) {
if (n > 0 && nm[0] != '\0' && r >= MIN_WAGE) {
no = n;
strncpy(name, nm, MAX_NAME); // copy first MAX_NAME characters
name[MAX_NAME] = '\0'; // ensure that last byte is null
rate = r;
} else {
Employee temp;
*this = temp;
}
}
void Employee::display() const {
if (no > 0) {
cout << fixed << setprecision(2);
cout << name << " (" << no << ") $" << rate;
}
else
cout << "no data available";
}
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Your Task
Upgrade the Employee
module to overload the following operator:
- += operator increases the wage
rate of the current object by the amount of the right operand
and returns a reference to the current object
Client Module
The client program that uses the upgraded class looks something
like
// Member Operator
// h8.cpp
#include <iostream>
using namespace std;
#include "Employee.h"
int main() {
Employee null,
mark(3456, "Mark"),
rose(3457, "Rose", 10.70);
null.display();
cout << endl;
null += 0.50; // raise of 50 cents
null.display();
cout << endl;
mark.display();
cout << endl;
mark += 0.50; // raise of 50 cents
mark.display();
cout << endl;
rose.display();
cout << endl;
rose += 0.50; // raise of 50 cents
rose.display();
cout << endl;
}
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no data available
no data available
Mark (3456) $10.25
Mark (3456) $10.75
Rose (3457) $10.70
Rose (3457) $11.20
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Employee Module
Employee.h
Add the prototype declaration to the class definition:
// Employee - Header File
// Employee.h
const double MIN_WAGE = 10.25;
const int MAX_NAME = 20;
class Employee {
int no;
char name[MAX_NAME + 1];
double rate;
public:
Employee();
Employee(int, const char*);
Employee(int, const char*, double);
void display() const;
};
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Employee.cpp
Add your operator definition to the implementation file:
// Employee - Implementation File
// Employee.cpp
#include <iostream>
#include <iomanip>
#include <cstring>
#include "Employee.h"
using namespace std;
Employee::Employee() {
// safe empty state
no = 0;
name[0] = '\0';
rate = MIN_WAGE;
}
Employee::Employee(int n, const char* nm) {
Employee temp(n, nm, MIN_WAGE);
*this = temp;
}
Employee::Employee(int n, const char* nm, double r) {
if (n > 0 && nm[0] != '\0' && r >= MIN_WAGE) {
no = n;
strncpy(name, nm, MAX_NAME); // copy first MAX_NAME characters
name[MAX_NAME] = '\0'; // ensure that last byte is null
rate = r;
} else {
Employee temp;
*this = temp;
}
}
void Employee::display() const {
if (no > 0) {
cout << fixed << setprecision(2);
cout << name << " (" << no << ") $" << rate;
}
else
cout << "no data available";
}
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