Part C - Encapsulation
Expressions
Workshop 6
In this workshop, you are to design a class that
evaluates expressions involving fractions.
Learning Outcomes
Upon successful completion of this workshop, you will have
demonstrated the abilities to
- overload an operator as a member function
- overload an operator as a helper function
- overload an operator as a friend function
Fraction Calculator - All Groups
Fraction Class
Define a class named Fraction that
holds the data for a rational number. The fraction may be
positive or negative valued. If you completed workshop 2,
you may upgrade that solution to meet the specifications below.
Include in your class design the following functions:
- Fraction() - a no-argument constructor
that sets the state of the current object to a safe empty state
- Fraction(int, int) - a two-argument constructor
that receives the fraction's numerator and denominator
- void simplify() - a private member function
that simplifies the numerator and denominator to lowest denominator
form.
- void display() const - a query that
displays the fraction in numerator/denominator
form on standard output
- Fraction& operator+=(const Fraction& f) -
a member operator that adds Fraction f
to the current object - and returns a reference to the current object
- Fraction operator+(const Fraction&, const Fraction&) -
a non-friend helper operator that adds two Fraction
objects and returns a copy of the result
- bool operator==(const Fraction&, const Fraction&) - a friend operator that compares
two Fraction objects for equality
Make sure to call your simplify() member function from
your other functions whenever appropriate.
Place your class definition in a header file named
Fraction.h and your function
definitions in an implementation file named Fraction.cpp.
Client Module
The main module that uses your Fraction
class is listed on the left, while the results of execution are listed
on the right:
// Workshop 6 - Fraction Calculator
// w6.cpp
#include <iostream>
using namespace std;
#include "Fraction.h"
void read(const char* msg, Fraction& f) {
int num, den;
cout << "Enter " << msg; << endl;
cout << " Numerator : ";
cin >> num;
cout << " Denominator : ";
cin >> den;
f = Fraction(num, den);
}
int main() {
Fraction left, right, result, ref;
cout << "Fraction Calculator\n";
cout << "===================\n";
read("Left Operand : ", left);
read("Right Operand : ", right);
cout << "Result : " << endl;
left.display();
cout << " + ";
right.display();
cout << " = ";
result = left + right;
result.display();
cout << endl;
read("2nd Right Operand : ", right);
cout << "Result : " << endl;
result.display();
cout << " += ";
right.display();
cout << " => ";
result += right;
result.display();
cout << endl;
read("Reference : ", ref);
if (result == ref)
cout << "Result == Reference" << endl;
else
cout << "Result != Reference" << endl;
}
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Fraction Calculator
===================
Enter Left Operand :
Enter numerator : 1
Enter denominator : 6
Enter Right Operand :
Enter numerator : 1
Enter denominator : 3
Result :
1/6 + 1/3 = 1/2
Enter 2nd Right Operand :
Enter numerator : 1
Enter denominator : 3
Result :
1/2 += 1/3 => 5/6
Enter Reference :
Enter numerator : 10
Enter denominator : 12
Result == Reference
|
Upgrade - Group Y
Design and code the Fraction class described
above. Add to your class design the following member functions:
- Fraction& operator-=(const Fraction& f) -
a member operator that subtracts Fraction f
from the current object and returns a reference to the current object
- Fraction operator*=(const Fraction& f) -
a member operator that multiplies the current object by
Fraction f and returns a reference to
the current object
- Fraction operator/=(const Fraction& f) -
a member operator that divides the current object by
Fraction f and returns a reference to
the current object
Main Program
The main module that uses your Fraction class is listed on the left, while the results
of execution are listed on the right:
// Workshop 6 - Fraction Calculator
// w6.cpp
#include <iostream>
#include <cstring>
using namespace std;
#include "Fraction.h"
void read(const char* msg, Fraction& f) {
int num, den;
cout << "Enter " << msg << endl;
cout << " Numerator : ";
cin >> num;
cout << " Denominator : ";
cin >> den;
f = Fraction(num, den);
cin.ignore();
}
int main() {
char op[3];
bool quit = false;
Fraction left, right, result, ref;
cout << "Fraction Calculator\n";
cout << "===================\n";
read("Left Operand : ", left);
do {
cout << "+= -= *= /= ## to quit : ";
cin.get(op, 3);
char c = cin.get();
if (c != '\n' ||
op[1] != '=' && op[1] != '#') {
cerr << "Try Again!" << endl;
cin.ignore(2000, '\n');
}
else if (strcmp(op, "##") == 0) {
read("Reference : ", ref);
quit = true;
}
else {
read("Right Operand : ", right);
cout << "Result : " << endl;
left.display();
switch (op[0]) {
case '+':
cout << " += ";
left += right;
break;
case '-':
cout << " -= ";
left -= right;
break;
case '*':
cout << " *= ";
left *= right;
break;
case '/':
cout << " /= ";
left /= right;
break;
}
right.display();
cout << " => ";
left.display();
cout << endl;
}
} while (!quit);
if (left == ref)
cout << "Result == Reference"
<< endl;
else
cout << "Result != Reference"
<< endl;
}
|
Fraction Calculator
===================
Enter Left Operand :
Numerator : 1
Denominator : 6
+= -= *= /= ## to quit : +=
Enter Right Operand :
Numerator : 1
Denominator : 3
Result :
1/6 += 1/3 => 1/2
+= -= *= /= ## to quit : *=
Enter Right Operand :
Numerator : 1
Denominator : 3
Result :
1/2 *= 1/3 => 1/6
+= -= *= /= ## to quit : -=
Enter Right Operand :
Numerator : 1
Denominator : 12
Result :
1/6 -= 1/12 => 1/12
+= -= *= /= ## to quit : /=
Enter Right Operand :
Numerator : 3
Denominator : 4
Result :
1/12 /= 3/4 => 1/9
+= -= *= /= ## to quit : ##
Enter Reference :
Numerator : 2
Denominator : 18
Result == Reference
|
SUBMISSION
Typescript
Create a typescript of your complete solution
using the following commands:
+ At the prompt, type: script w6.txt
+ At the prompt, type: whoami
+ At the prompt, type: cat Fraction.h Fraction.cpp
+ At the prompt, type: g++ -o w6 w6.cpp Fraction.cpp
+ At the prompt, type: w6
+ At the input prompt, enter test data
+ At the prompt type: exit
|
These commands will produce a file named w6.txt. Download this file to your local
computer.
Moodle
Upload your typescript file to Moodle:
- Login to Moodle
- Select your course code
- Select W6 under Assignments and Tasks
- Upload w6.txt
- Write a short note to your instructor
- press "Edit"
- enter your conclusions about this workshop in the notes textbox
- press "Save Changes"
- When ready to submit, press "Send for Marking"
Other Submissions
Submit your typescript file as your instructor has specified.
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