Unit_2_OOP.pdf

GLS UNIVERSITY iMSCIT Sem-III 221601301 Object Oriented Programming  Unit – II Classes, Objects & Functions  Overview of C++ Language  Class & Objects in C++  Constructor & Destructor  Data Members...

GLS UNIVERSITY iMSCIT Sem-III 221601301 Object Oriented Programming  Unit – II Classes, Objects & Functions  Overview of C++ Language  Class & Objects in C++  Constructor & Destructor  Data Members  Constructor Access Specifiers Types of Constructor  Member Functions – Default, Declaration, Definition, Calling – Parameterised, Default Arguments – Copy Inline functions Constructor Overloading Function overloading  Destructor This pointer  Friend function & Friend class C++ Classes/Objects C++ is an object-oriented programming language. Everything in C++ is associated with classes and objects, along with its attributes and methods. For example: in real life, a car is an object. The car has attributes, such as weight and color, and methods, such as drive and brake. Attributes and methods are basically variables and functions that belongs to the class. These are often referred to as "class members". A class is a user-defined data type that we can use in our program, and it works as an object constructor, or a "blueprint" for creating objects. Create a Class To create a class, use the class keyword: Example Create a class called "MyClass": class MyClass { // The class public: // Access specifier int myNum; // Attribute (int variable) string myString; // Attribute (string variable) }; Create a Class  The class keyword is used to create a class called MyClass.  The public keyword is an access specifier, which specifies that members (attributes and methods) of the class are accessible from outside the class. You will learn more about access specifiers later.  Inside the class, there is an integer variable myNum and a string variable myString. When variables are declared within a class, they are called attributes.  At last, end the class definition with a semicolon ;. Create an Object  In C++, an object is created from a class. We have already created the class named MyClass, so now we can use this to create objects.  To create an object of MyClass, specify the class name, followed by the object name.  To access the class attributes (myNum and myString), use the dot syntax (.) on the object: Create an Object #include #include using namespace std; class MyClass { // The class public: // Access specifier int myNum; // Attribute (int variable) string myString; // Attribute (string variable) }; int main() { MyClass myObj; // Create an object of MyClass // Access attributes and set values myObj.myNum = 15; myObj.myString = "Some text"; // Print values cout