CPSC 231 C++ Review1 Learning Objectives §Review of the object oriented design goals. §Review of C++ classes l data members l member functions (methods) l constructors l destructors

CPSC 231 C++ Review2 C++ Classes §Classes enable programmers to model objects that have attributes (data members) and behaviors (member functions or methods) §Once a class has been defined, the class name can be used to declare objects of that class.

CPSC 231 C++ Review3 A Simple C++ Class #include // a Box class class Box { private: int height, width, depth; // private data members public: Box(int, int, int); // constructor function ~Box(); // destructor function int volume(); // member function (computev olume) };

CPSC 231 C++ Review4 Class Box the constructor function Box::Box(int ht=0, int wd=0, int dp=0) { height = ht; width = wd; depth = dp; } // the destructor function Box::~Box() { // does nothing } //

CPSC 231 C++ Review5 Class Box cont. // member function to compute the Box's volume int Box::volume() { return height * width * depth; } // an application to use the box int main() { Box b, thisbox(7,8,9); // declare a Box cout <<b.volume()<<' '<<thisbox.volume(); // compute & display return 0; }

CPSC 231 C++ Review6 Example of a SalesPerson Class // salesp.h p 384 of D&D // SalesPerson class definition // Member functions defined in salesp.cpp #ifndef SALESP_H #define SALESP_H class SalesPerson { public: SalesPerson(); // constructor void getSalesFromUser(); // get sales figures from keyboard void setSales( int, double ); // user supplies data void printAnnualSales();

CPSC 231 C++ Review7 SalesPerson class definition cont. private: double totalAnnualSales(); // utility function double sales[ 12 ]; // 12 monthly sales figures }; #endif

CPSC 231 C++ Review8 Member Functions for Class SalesPerson // salesp.cpp // Member functions for class SalesPerson #include #include "salesp.h" // Constructor function initializes array SalesPerson::SalesPerson() { for ( int i = 0; i < 12; i++ ) sales[ i ] = 0.0; }

CPSC 231 C++ Review9 “get” function getSalesFromUser // Function to get 12 sales figures from the user // at the keyboard void SalesPerson::getSalesFromUser() { double salesFigure; for ( int i = 0; i < 12; i++ ) { cout << "Enter sales amount for month " << i + 1 << ": "; cin >> salesFigure; setSales( i, salesFigure ); }

CPSC 231 C++ Review10 “set” function setSales // Function to set one of the 12 monthly sales figures. // Note that the month value must be from 0 to 11. void SalesPerson::setSales( int month, double amount ) { if ( month >= 0 && month 0 ) sales[ month ] = amount; else cout << "Invalid month or sales figure" << endl; }

CPSC 231 C++ Review11 “print” function printAnnualSales // Print the total annual sales void SalesPerson::printAnnualSales() { cout << setprecision( 2 ) << setiosflags( ios::fixed | ios::showpoint ) << "\nThe total annual sales are: $" << totalAnnualSales() << endl; }

CPSC 231 C++ Review12 “utility” function totalAnnualSales // Private utility function to total annual sales double SalesPerson::totalAnnualSales() { double total = 0.0; for ( int i = 0; i < 12; i++ ) total += sales[ i ]; return total; }

CPSC 231 C++ Review13 Sample driver // Compile with salesp.cpp #include #include "salesp.h" int main() { SalesPerson s; // create SalesPerson object s s.getSalesFromUser(); // note simple sequential code s.printAnnualSales(); // no control structures in main return 0; }