README.md

Essentials Fundamental:

• Fundamentals
• How Computers Works
• Introduction to Number System
• What is a Program
• Low-level & High-level languages
• Compiler vs Interpreter
• What is an Operating System

Program Development:

• Programming Paradigms Methodologies
• What is an algorithm
• What is a Flow-chart
• Steps for Program Development & Execution

C++ Basic:

• Data Types, Variables
• Operators
• Compound Assignment Operator
• Overflow of data-types
• Bitwise Operators
• Logical Operator
• enum & typedef

Conditional Statements:

• If and else is used for writing conditional statement.
• If condition is true then if block is executed.
• If condition is false then else block is executed.
• 0 => means false.
• 1 => means true or non-zero value is also true.
• If can be nested inside if as well as else statement.
• Nesting of is also written as else-if ladder.

Loops:

• Loops are iterative statements.
• Block of statements are repeatedly executed as long as condition is true.
• Condition given in loop must become false after some finite iterations otherwise its a infinite loop.
• Values used in condition must update inside the body of finite loop.
• Four types of loops:
  • pre-tested loop while()
  • post-tested loop do..while()
  • counter controlled loop for()
  • for each loop for Collections for()

Arrays:

• Array is a collection of similar data elements under one name, each element is accessible using its index.
• Memory for array is allocated contiguously.
• for-each loop is used for accessing array.
• N-dimension arrays are supported by C++.
• Two-Dimensional Arrays are sued for Matrices.
• Array can be created in Stack or Heap Section of memory.

Pointer:

• Pointer is address variable.
• It can store the address of data.
• Pointer are used for accessing heap memory.
• 5 Arithmetic operations are allowed pointer:
  • p++ => move pointer to next element.
  • p-- => move pointer to previous element.
  • p+k => gives address of kth element form pointer location to right.
  • p-k => gives address of kth element from pointer location to left.
  • q-p => gives number of elements between 2 pointers p and q.
• Pointers can be of many levels.
• Double pointer is used for accessing 2D arrays.

Reference:

• Reference is a Alias of variable.
• It must be initialised when declared.
• It doesn’t take any memory.
• It cannot be modified to refer other variable.
• Syntax for reference declaration is.
• Int &y = x;

Functions:

• Function is a module which performs a specific task
• Functions are called by name
• Rules for giving function name is same as variable name
• Function can take 0 or more parameters
• Function can return single value
• Void function don’t return any value
• Default return type is int

Function Overloading:

• If More than one functions can have same name, but different parameter list, then they are overloaded functions
• Return the is not considered in overloading
• Function overloading is used for achieving compile time polymorphism

Function Template:

• Function template are used for defining generic functions
• They work for multiple datatypes
• Datatype is decided based on the type of value passed
• Datatype is a template variable
• Function can have multiple template variables

Call by Address:

• Address pf actual parameters are passed.
• Formal parameters must be pointers
• Formal parameters ca indirectly access actual parameters.
• Changes done using formal parameters will reflect in actual parameters

Return by Address:

• A function can return address of memory
• It should not return address of local variables, which will be disposed after function ends
• It can return address of memory allocated in heap

Return by Reference

• A function cal return reference
• It should not return reference of its local variables
• It can return formal parameters if they are reference

Default Arguments

• Parameters of a function can have default values
• If a parameter is default then , passing its value is options
• Function with default argument can be called with variable number of argument
• Default values to parameters must be given from right side parameter
• Default arguments are much useful in constructors
• Default arguments are useful for defining overloaded functions

Static variables

• They have local scope but remain in memory thru out the execution of program
• They are created in code section
• They are history-sensitive

Object-Oriented Programming:

• Features of OOPS:
  • Abstraction
  • Data Hiding
  • Inheritance
  • Polymorphism

Classes:

• Class is a blue print of an object.
• Class in a group of objects.
• Class is a design of object.

Many object can be created from same class:

• Object consumes memory equal to sum of sizes of all data members
• Member functions don’t occupy memory
• Member functions are called depending on object
• . Dot operator is used for accessing members of object
• Memory allocated for object is also called as instance

A pointer of type class can be created:

• A pointer can point on existing object
• A new object can be created in heap using pointer
• Arrow operator is used for accessing members of an object using pointer

Data Hiding:

• Data members of a class class are usually declared as Private or Protected,
• They can be accessed only inside the class and child classes
• Data finding protects data from mishandling

Constructors:

• Constructor is a member function of a class
• It will have same name as class name
• It will not have return type
• Its should be public
• It can be declared as private also in some cases
• It is called when object is created
• It is used for initialising an object
• It can be overloaded
• If its not defined then class will have a default constructor
• Constructor can take default arguments

Types of constructors:

• Non-argument constructor
• Parameterised constructor
• Copy constructor

All types of Member Functions:

• Constructors - called when object is created
• Accessors - used for knowing the value of data members
• Mutators - used for changing value of data member
• Facilitator - actual functions of class
• Enquiry - used for checking if an object satisfies some condition
• Destructor - used for releasing resources used by object

Operator Overloading:

• Operator overloading is a compile-time polymorphism in which the operator is overloaded to provide the special meaning to the user-defined data type. Operator overloading is used to overload or redefines most of the operators available in C++. It is used to perform the operation on the user-defined data type. For example, C++ provides the ability to add the variables of the user-defined data type that is applied to the built-in data types.
• The advantage of Operators overloading is to perform different operations on the same operand.

Inheritance:

• Acquiring the feature of existing class into a new class.
• Deriving a class from a existing class.

Access Specifiers:

• Private -> Accessible only inside a class
• Protected -> Accessible inside a class and inside derived classes
• Public -> accessible inside class, inside derived class and upon object

Ways of inheritance:

• A class can be inherited in flowing ways
• Publicly -> All members of base will have same accessibility in derived class
• Protectedly -> All members of base will become protected in derived class
• Privately -> All members of base will become private in derived class

Base class Pointer pointing to derived class object

• Base class pointer can point on derived class object.

• But only those functions which are in base class, can be called.

• If derived class is having overrides functions they will not be called unless base class functions are declared as virtual.

• Derived class pointer cannot point on base class object

  Example 1

  class Base
  {
  public:
    void fun1()
    {
      cout<<"fun1 of Base"<<endl;
    }
  };
  

  Example 2

  class Derived: public Base
  {
  public:
    void fun2()
    {
      cout<<"fun2 of Derived"<<endl;
    }
  };
  
  class Rectangle
  {
  public:
    void area()
    {
      cout<<"Area of Rectangle"<<endl;
    }
  };
  
  class Cuboid: public Rectangle
  {
  public:
    void volume()
    {
      cout<<"Volume of Cuboid"<<endl;
    }
  };
  
  

  Example 3

  class BasicCar
  {
  public:
    void start()
    {
      cout<<"Car started"<<endl;
    }
  };
  
  class AdvanceCar: public BasicCar
  {
  public:
    void playMusic()
    {
      cout<<"Music Playing"<<endl;
    }
  };
  
  

Virtual Functions

• Virtual functions are used for achieving polymorphism

• Base class can have virtual functions

• Virtual functions can be overrides in derived class

• Pure virtual functions must be overrides by derived class

  Example:

  class BasicCar
  {
  public:
    virtual void start(){cout<<"BasicCar started"<<endl;}
  };
  
  class AdvanceCar: public BasicCar
  {
  public:
    void start(){cout<<"AdvanceCar Started"<<endl;}
  };
  
  int main()
  {
    BasicCar *p=new AdvanceCar();
    p->start();
  }
  

Polymorphism

• Same name different actions

• Runtime Polymorphism is achieved using function overriding

• Virtual functions are abstract functions of base class

• Derived class must override virtual function

• Base class pointer pointing to derived class object and a override function is called

  Summary: class car is defined, then sub classes override, then base class method made as virtual the pure virtual

  Example:

  
    class Car
    {
    public:
      virtual void start()=0;
    };
  
    class Innova:public Car
    {
    public:
      void start(){cout<<"Innova Started"<<endl;}
    };
  
    class Swift:public Car
    {
    public:
      void start(){cout<<"Swift Started"<<endl;}
    };
  
    int main()
    {
      //Car c;
      Car *p=new Innova();
      p->start();
      p=new Swift();
      p->start();
    }
  

  When we assign virtual function to 0. It is pure virtual function. Those function are must be overidded by the derived class.

Abstract class:

• Class having pure virtual function is a abstract class
• Abstract class can have concrete also.
• Object of abstract class cannot be created
• Derived class can must override pure virtual function, otherwise it will also become a abstract class.
• Pointer of abstract class can be created
• Pointer of abstract class can hold object of derived class
• Abstract classes are used for achieving polymorphism
• Base class can be:
  • Concrete
  • Abstract with some concrete and some pure virtual functions
  • All virtual functions

Example:

```
class Base //Abstract Class
{
public:
  virtual void fun1()=0;
  virtual void fun2()=0;
};

class Derived :public Base
{
public:
  void fun1()
  {
    cout<<"fun1 of Derived"<<endl;
  }
  void fun2()
  {
    cout<<"fun2 of Derived"<<endl;
  }
};

int main()
{
  Derived d;
  d.fun1();
  d.fun2();
}
```

Static Members

• Static data members are members of a class

• Only one instance of static members is created and shared by all objects

• They can be accessed directly using class name

• Static members functions are functions of a class, they can be called using class name, without creating object of a class.

• They can access only static data members of a class, they cannot access non-static members of a class.

  Example:

  ```
  class Student{
    public:
      int rollNo;
      static int admissionNo;
  
      Student()
      {
        admissionNo;
        rollNo = admissionNo;
      }
  };
  
  int Student::admissionNo = 0;
  ```