Member Initializer List-Object Oriented Programming-Lecture Slides, Slides of Object Oriented Programming

Download Member Initializer List-Object Oriented Programming-Lecture Slides and more Slides Object Oriented Programming in PDF only on Docsity! Object Oriented Programming (OOP) I -Toia0 dom \ On Review ►this Pointer ►Separation of interface and implementation ►Constant member functions docsity.com Modified Student Class class Student{ … const int rollNo; public: Student(int aNo); int getRollNo(); void setRollNo(int aNo); … }; docsity.com Example Student::Student(int aRollNo) { rollNo = aRollNo; /*error: cannot modify a constant data member*/ } docsity.com Example void Student::SetRollNo(int i) { rollNo = i; /*error: cannot modify a constant data member*/ } docsity.com Order of Initialization ►Data member are initialized in order they are declared ►Order in member initializer list is not significant at all docsity.com Example class ABC{ int x; int y; int z; public: ABC(); }; docsity.com Example ABC::ABC():y(10),x(y),z(y) { … } /* x = Junk value y = 10 z = 10 */ docsity.com Example class Student{ … int rollNo; public: … int getRollNo(){ return rollNo; } }; docsity.com Example int main(){ const Student aStudent; int a = aStudent.getRollNo(); //error } docsity.com const Objects ►const objects cannot access “non const” member function ►Chances of unintentional modification are eliminated docsity.com Constant data members ►Make all functions that don’t change the state of the object constant ►This will enable constant objects to access more member functions docsity.com Static Variables ►Lifetime of static variable is throughout the program life ►If static variables are not explicitly initialized then they are initialized to 0 of appropriate type docsity.com Example void func1(int i){ static int staticInt = i; cout << staticInt << endl; } int main(){ func1(1); func1(2); } Output: 1 1 docsity.com Class vs. Instance Variable ►Student s1, s2, s3; Class Space s1(rollNo,…) s2(rollNo,…) s3(rollNo,…) Instance Variable Class Variable docsity.com Static Data Member (Syntax) ►Keyword static is used to make a data member static class ClassName{ … static DataType VariableName; }; docsity.com Defining Static Data Member ►Static data member is declared inside the class ►But they are defined outside the class docsity.com Example class Student{ private: static int noOfStudents; public: … }; int Student::noOfStudents = 0; /*private static member cannot be accessed outside the class except for initialization*/ docsity.com Initializing Static Data Member ►If static data members are not explicitly initialized at the time of definition then they are initialized to 0 docsity.com Example int Student::noOfStudents; is equivalent to int Student::noOfStudents=0; docsity.com