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C++ File Processing

We will learn to read and write files from C++ in this chapter.

To do that, first of all we need to include a header file from Standard C++ Library named fstream.

fstream is combined with two data separate library files which are:

· ofstream – Output file stream that creates and writes information to files.

· ifstream – Input file stream that read information from files.

So,…

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C++ Exceptions

There are several problems that occur during program execution or after user input which will crash or terminate the program without any clue for that if we do not apply exceptions handling methods to handle those exceptions.

C++ exceptions is built with three keywords:

try{

throw

catch(){

}

try– try block is used before the block of code where exceptions may generate after execution. It will…

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C++ Template Specialization

When we use regular templates for functions or classes. The templates handle different data types in the same way as the same code is used for compilation of all data types.

· But in case we need a specific data type for a particular argument or parameter. We use the method of Template specialization where we override the default template implementation to handle a particular type in a different…

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C++ Class Templates

As like the function templates we can define a class template with the help of same syntax we learned in the previous chapter.

Example:

#include <iostream>

using namespace std;

template<class R> //alternative template<typename R>

class DisplayGreater{

private:

R a,b; //two generic private member variables declared

public:

DisplayGreater(R x, Ry) //constructor is used to initialize the…

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C++ Function Templates

Till now we already work with many functions and in every program there is at least one default function i.e. the main function.

As you know that we have declare a return type and parameters to declare a function.

#include <iostream>

using namespace std;

int show(int a){

return a;

}

int main() {

int x = 5;

cout<<show(x);

return 0;

}

// Output 5

· If we go through…

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C++ Abstract Classes

Pure Virtual Functions

· Pure virtual functions are simply represented by the blank virtual function in the base class which does not have any body.

· Virtual member function without definition is called pure virtual function.

And to represent it correctly we need to code it like below:

//Base Class

class Cars {

public:

virtual void SetPower()= 0;

}

· They specify that…

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C++ Virtual Functions

The member function which is declared within the base class and then redefined by a derived class by using the same function name.

To create a virtual function, we need to precede the base class member function with the virtual keyword:

//Base Class

class Cars {

public:

virtual void SetPower(){

}

};

· When the virtual function is inherited from the base class, the derived class…

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C++ Polymorphism

“Poly” means “many” and “morph” means “form”.

· Polymorphism is the ability of an object (or reference) to assume (be replaced by) or become many different forms of object.

· Polymorphism is briefly described as “one interface, many implementations.”

There are two types of polymorphism one is Compile-Time Polymorphism and the other is Run-Time Polymorphism.

Compile Time…

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C++ Derived Constructor and Destructor

As we already learn in the exceptions of Inheritance that Constructor and Destructor are not inherited from the base class.

But when the object of the Derived class is being created or deleted, the Constructor and Destructor of Base class can be called from the main function().

Example:

#include <iostream>

using namespace std;

// Base class

class Cars

{

public:

Cars() //Base Class…

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C++ Protected Members

We already learn about Encapsulation and the two important access specifiers, which are public and private.

Let me recap,

Public: May be accessed from anywhere outside the class.

Private: Accessed within their class and the outsiders can have used the friend function.

But the third access specifier is still left and we need to learn that now.

That one is protectedwhich is similar to private…

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C++ Inheritance

As we know we humans classify humans on the basis of our language, from where we belong, etc.

· Such as Chinese, Nigerian, Indian, American all are derived from the base class Humans. But still they are classified on the basis of their place of belonging.

· Thus even the Chinese people have two eyes, one nose, two ears, one mouth and blood with a colour of red as like others do.

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C++ Operator Overloading

In case of Operator Overloading we overload operator to use the operator with user defined types.

For Example: ‘*’ multiplication operator can be overloaded to add two objects together.

In C++ Except five operators, all other Operators can be overloaded. And the five Operators which can’t be overloaded are:

1. sizeof – size of Operator

2. :: – Scope Operator

3. . – Member…

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C++ This Pointer

Sometimes in C++ we need to access the address of an object and that time use this pointer.

#include <iostream>

using namespace std;

class Keyword{ // A class is Declared

public:

Keyword(int a, int b) //Regular Constructor initialized with two parameters

:x(a),y(b)

{

}

void printOut(){

sum = x+y;

cout<<“The sum is(using keyword): “<<this-…

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C++ Friend Keyword

As we know the Encapsulation rules that there are different Access specifiers to access certain objects and variables.

Private specifiers cannot be accessed from outside the class.

But if we use the friend keyword as prefix before a non- member external function then we can access the private members.

#include <iostream>

using namespace std;

class Keyword{ // A class is Declared

public:

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C++ Member Initializer

There are situations when we need to work with both constant variable and regular variable.

But during the initialization of a constructor we declare one regular variable and one const variable then the program returns error.

Example without Member initializer:

Header file (.h):

#ifndef NEWCLASS_H_ // If not Defined

#define NEWCLASS_H_ // Then Define

class NewClass {

public:

NewClass(

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C++ Member Initializer

There are situations when we need to work with both constant variable and regular variable.

But during the initialization of a constructor we declare one regular variable and one const variable then the program returns error.

Example without Member initializer:

Header file (.h):

#ifndef NEWCLASS_H_ // If not Defined

#define NEWCLASS_H_ // Then Define

class NewClass {

public:

NewClass(int

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C++ Constants

Constant is an expression with a fixed value assigned to it and it cannot be changed until program terminates.

In case of constants we use the const keyword before the datatype during declaration of a variable.

const int x = 25;

const variables must be initialised during creation as we initialised here with 25.

Const Objects:

int main()

{

constNewClass NewOb; //New constant Object is…

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