Riyadh Philanthropic Society For Science Prince Sultan College For Woman

1. Riyadh Philanthropic Society For Science Prince Sultan College For Woman Dept. of Computer & Information Sciences CS 102 Computer Programming II (Lab: Defining Classes)

2. continue • Exercise • Complete the five missing parts in the following program: • #include<iostream> • #include<cmath> • using namespace std; • class Loan • { • public: • Loan(double the_amount, double the_rate, int the_term); • Loan( ); • void display( ); • double payment( ); • private: • double amount; // $ amount of the loan • double rate; // annual interest rate • int term; // number of months, length of the loan • }; Lab: Defining Classes 1

3. continue • Exercise • int main( ) • { • //1. Declare two loan objects: loan1 (initialized to given values) and • // loan2 (initialized to default values) • cout << "Display loan1: \n"; • loan1.display(); • //2. Display all information about loan2 • cout << "Monthly payment of loan1 = " << loan1.payment() << endl; • loan2 = loan1; • cout << "Monthly payment of loan2 = " << loan2.payment() << endl; • return 0; • } Lab: Defining Classes 2

4. Exercise • Loan::Loan(double the_amount, double the_rate, int the_term) • { • //3. Initialize the loan amount to the_amount, the loan rate to the_rate • // and the loan term to the_term • } • //4. Write the definition of the default constructor and initialize all member • // variables to zero • void Loan::display() • { • //5. Display all information about the loan, i.e. amount, rate, and term • } • double Loan::payment() • { • double fraction_rate = rate / 1200; • return (amount * fraction_rate * (pow((fraction_rate + 1),term) / • (pow((fraction_rate+1),term) - 1))); • } Lab: Defining Classes 3

5. continue • Solution • #include<iostream> • #include<cmath> • using namespace std; • class Loan • { • public: • Loan(double the_amount, double the_rate, int the_term); • Loan( ); • void display( ); • double payment( ); • private: • double amount; // $ amount of the loan • double rate; // annual interest rate • int term; // number of months, length of the loan • }; Lab: Defining Classes 4

6. continue • Solution • int main( ) • { • Loan loan1(1000,5,10), loan2; • cout << "Display loan1: \n"; • loan1.display(); • cout << "Display loan2: \n"; • loan2.display(); • cout << "Monthly payment of loan1 = " << loan1.payment() << endl; • loan2 = loan1; • cout << "Monthly payment of loan2 = " << loan2.payment() << endl; • return 0; • } Lab: Defining Classes 5

7. continue • Solution • Loan::Loan(double the_amount, double the_rate, int the_term) • { • amount = the_amount; • rate = the_rate; • term = the_term; • } • Loan::Loan() • { • amount = 0; • rate = 0; • term = 0; • } Lab: Defining Classes 6

8. Solution • void Loan::display() • { • cout << "Amount = " << amount << endl • << "Rate = " << rate << endl • << "Term = " << term << endl; • } • double Loan::payment() • { • double fraction_rate = rate / 1200; • return (amount * fraction_rate * (pow((fraction_rate + 1),term) / • (pow((fraction_rate+1),term) - 1))); • } Lab: Defining Classes 7

9. Exercise • Write a class called Rectangle that represents a rectangle as a pair of • double values - the rectangle length and width. • Your class should include the following member functions: • A constructor with two arguments that sets the length and • width to the values specified by its arguments. • A get_length function that gets the length of the rectangle. • A get_width function that gets the width of the rectangle. • Note: test the class. Lab: Defining Classes 8

10. continue • Solution • #include<iostream> • using namespace std; • class Rectangle • { • public: • Rectangle(double the_length, double the_width); • double get_length(); • double get_width(); • private: • double length; • double width; • }; Lab: Defining Classes 9

11. continue • Solution • int main( ) • { • Rectangle rectangle1(1,2); • cout << "Length of rectangle1 = " << rectangle1.get_length() << endl • << "Width of rectangle1 = " << rectangle1.get_width() << endl; • return 0; • } • Rectangle::Rectangle(double the_length, double the_width) • { • length = the_length; • width = the_width; • } Lab: Defining Classes 10

12. Solution • double Rectangle::get_length() • { • return length; • } • double Rectangle::get_width() • { • return width; • } Lab: Defining Classes 11

13. Exercise • Add the following member functions to the Rectangle class: • A default constructor that sets the length and width to 0.0. • An area function that returns the area of the rectangle. • (length times width) • A perimeter function that returns the perimeter of the rectangle. • (2 times length plus 2 times width) • Note: test the new functions. Lab: Defining Classes 12

14. continue • Solution • #include<iostream> • using namespace std; • class Rectangle • { • public: • Rectangle(double the_length, double the_width); • Rectangle( ); • double get_length(); • double get_width(); • double area(); • double perimeter(); • private: • double length; • double width; • }; Lab: Defining Classes 13

15. continue • Solution • int main( ) • { • Rectangle rectangle1(1,2),rectangle2; • cout << "Length of rectangle1 = " << rectangle1.get_length() << endl • << "Width of rectangle1 = " << rectangle1.get_width() << endl; • cout << "Length of rectangle2 = " << rectangle2.get_length() << endl • << "Width of rectangle2 = " << rectangle2.get_width() << endl; • double area = rectangle1.area(); • double perimeter = rectangle1.perimeter(); • cout << "Area of rectangle1 = " << area << endl • << "Perimeter of rectangle1 = " << perimeter << endl; • return 0; • } Lab: Defining Classes 14

16. continue • Solution • Rectangle::Rectangle(double the_length, double the_width) • { • length = the_length; • width = the_width; • } • Rectangle::Rectangle( ) • { • length = 0; • width = 0; • } Lab: Defining Classes 15

17. Solution • double Rectangle::get_length() • { • return length; • } • double Rectangle::get_width() • { • return width; • } • double Rectangle::area() • { • return length * width; • } • double Rectangle::perimeter() • { • return 2 * length + 2 * width; • } Lab: Defining Classes 16