Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16COSC 181 – Foundations of Computer ProgrammingClass 6Defining the GradeBook ClassLine 9 – 17//GradeBook class definitionclass GradeBook{public://function that displays a messagevoid displayMessage(){cout << “Welcome to the Grade Book!” << endl;}};Classes have identifiers, just like variables  Follow same rulesBy convention, class identifiers begin with a capital letter.Uses “camel case” notation  FirstSecondEasier to readEvery class is enclosed in { }, with a ; after the closing bracketpublic: indicates that the affected part of the class (members and functions) are accessible by functions outside the class (i.e. – main())Using the GradeBook class in a programWant to “call” displayMessage() to display the message on the screenCan’t call a member function until you create an instance of the classLines 22 and 23 in Fig 3.1GradeBook myGradeBook;“GradeBook” type is defined because we included the GradeBook class in the codemyGradeBook.displayMessage();“dot operator”UML: Class DiagramsClasses represented as a rectangle with 3 compartmentsClasses NameClasses Attributes C++ Data Members (more on this later)Classes OperationsDefining Member Function w/ Parameters#include <string> //allows use of string typeusing std::stringusing std::getlineFig 3.3 – Lines 16 -22public:// function displays a welcome messagevoid displayMessage(string courseName){cout << “Welcome to the grade book for \n” << courseName << “!” << endl; }main() function – lines 26-40int main(){string nameOfCourse;GradeBook myGradeBook;cout << “Please enter the course name:” <<endl;getline( cin, nameOfCourse );cout << endl;myGradeBook.displayMessage( nameOfCourse)return 0;}getline(cin, nameOfCourse);Can’t use cin >> nameOfCourse;Output and Input Please enter the course name:COSC181 C++ ProgrammingWelcome to the grade book forCOSC181 C++ ProgrammingFunction Definition and CallsNote:Function Definitionvoid displayMessage(string courseName)Function CallmyGradeBook.displayMessage( nameOfCourse)Good Programming PracticesUse different names for passed arguments and corresponding variables in function definitionUse meaningful function and parameter identifiersUML: Class Diagram (Updated)• Remember• Class Name• Class Attributes• Class MethodsData Members : set and get FunctionsFig 3.5 – lines 15 -40class GradeBook {public:void setCourseName(string name){courseName = name; } string getCourseName(){return courseName;}void displayMessage(){cout << “Welcome to the grade book for\n” << getCourseName() << “!” << endl; }private:string courseName;};New main() functionint main(){string nameOfCourse;GradeBook myGradeBook;cout << “Initial course name is: “ << myGradeBook.getCourseName()<<endl;cout << “\nPlease enter the course name:” << endl;getline( cin, nameOfCourse );myGradeBook.setCourseName(nameOfCourse);cout << endl;myGradeBook.displayMessage();return 0;}New: Output and InputInitial course name is:Please enter the course name:COSC181 C++ ProgrammingWelcome to the grade book forCOSC181 C++ ProgrammingAdditional Main() Functionint main(){string nameOfCourse;GradeBook myGradeBook181;GradeBook myGradeBook381;cout << “\nPlease enter the course name of 181:” << endl;getline( cin, nameOfCourse );myGradeBook181.setCourseName(nameOfCourse);cout << “\nPlease enter the course name of 381:” << endl;getline( cin, nameOfCourse );myGradeBook381.setCourseName(nameOfCourse);cout << endl;myGradeBook181.displayMessage();myGradeBook381.displayMessage();return 0;}OutputWhat is the output of the previous program?Please enter the course name of 181:COSC181 C++ ProgrammingPlease enter the course name of 381:COSC381 C++ ProgrammingWelcome to the grade book forCOSC181 C++ ProgrammingWelcome to the grade book forCOSC381 C++ ProgrammingGradeBook ClassFig 3.5 (pg. 92)private: vs. public:fundamental approach for Object-Oriented design important for Software Engineering purposesCreates a layer of abstraction that protects an objects data from outside codeObject clients may have bugs that could be destructiveIf we don’t use objects with private members then clients have total access to the valuesAlways localize affects if possibleClients need not know how data is being storedGradeBook – Updated Class DiagramNameClass Attributes- means its privateClass Member Functions+ means its public() – include parameters here: - include type (if any) after