A Step up to all facets of C Programming

April 28, 2022.

Hopefully, I assume you are familiar with the C programming language, which is general purpose, fast, portable and widely used. In this article we will be concerned with the essence of C++ programming language.

Let's have a glimpse of C?

• C is an imperative procedural language, supports recursion and structured programming, also supports I/O, string manipulation and mathematical functions that are defined in the standard library.
• It is a statically typed language which is much closer to the system hardware not as much as assembly language.?
• It does basic operations - system friendly and compiler fine, over memory image.?
• Unlike Java, python etc., it has easy, faster executable, light code with less resource requirement.?
• We can hold pointers and can access or do whatever is allowed. Also, can create user-defined data types for effective and optimized program execution.
• One can define his own functions for code reusability, avoid redundancy, easier maintenance and modularity; store items of the same type and implement data structures and make use of character arrays for pattern searching; flexibility to allocate and deallocate memory dynamically.?
• Additionally it does Macro and source code file inclusion, conditional compilation and file input/output access.

Then, why C++ ? The hidden reason is Safety and convenience.?

In C, as it is procedural, there is no binding between data and functions, everything should be explicitly done to associate them. For large software systems, it is not a preferable way.

The right way is component wise building with added security and well structured. We have to shift to object-oriented programming for this.?

Notice real world items like refrigerators & televisions : Are they packaged, if so why??

Let's now look into this, those are packaged for convenient usage and to keep safe in both ways. Users are given only access to the control panel of the device and avoided to change internal voltages of circuit.

Similarly, our motive is to build a software component that is safe (less error prone) and convenient. We make use of struct gradually to build this software component for large software systems.

• Analogous to above examples, functionality associated with a structure is available to users only through member functions (Ex: control panel of the device).
• ?Internal things or actual implementation of modules is no way at risk of the user. Similar to above examples, there is no need for the user to know circuit connections and all other stuff.
• Need to know what to access (member function) and how it is achieved without direct access to data members.
• ?No need to relearn, If a better control panel is built for a device then no need to redesign the previous model. This is the same as, If you came with a better version of struct, but you can keep signatures of member functions the same.
• ?To do out of scope operations, when a variable gets out of scope, things could get out of reach. This can be achieved by suitably passing to member functions by reference.

Main features of C++

Encapsulation: Data Members are binded to Member functions or methods. Any intended operation could be done using these functions. External access of data members is restricted unless specified or allowed.

• Data hiding is achieved through this feature.

Abstraction: Internal details of implementation are put away from the user. Only relevant information is accessed for behavioral fulfillment of method.

• This feature is helpful to view complex structures as a black box and worry only about interface working.
• Detail hiding is achieved through this feature.

Classes and Objects: In a real-world scenario, an object is a distinguishable entity which has specific state, behavior and properties. These entities can be overlapped, generalized and even specialized.

• All objects of a similar kind possess the same set of possible properties, this information can be looked at as metadata and can be pre-specified as a blue-print so that the system can allocate? memory accordingly. This is nothing but, Class definition.
• When an object of the same class type is created, an instance of a class is generated with a local copy of its data.

For example consider the following code, which has fruit as a class and many fruits like apple, grapes can be created as an instance.

#include <bits/stdc++.h

using namespace std;

class fruit

{

????// members are by default private here

????/* data members */

public: //Access Specifier

????string name, color;

????double price;

?

????/* member functions */

????void print()

????{

????????cout << name << " " << color << " " << price <<???????

endl;

????}

};

int main()

{

????fruit obj;

????// object is created here

????obj.name="apple";

????obj.color="brown";

????obj.price=100;

????obj.print();

????return 0;

}

//Output:

//apple brown 100


>        

Members of class are: Data members: same as Attributes Member functions: does some operation over data members.

?Actually, there is a lot more to unfold. All those details are out of scope of this article. For detailed content follow the Reference section which is at the end of this article.

The basic idea is,

• Relating distinguishable individual entities and their functionality so that no other part of the code can access this data except the specified function.?
• Manipulating data among objects without knowing about others except the type.

?

Inheritance: As mentioned above objects can have overlapped properties. Classes can have similar properties and behavior with other classes. Additionally, it can have different members also.

• The class from which the properties derived is termed as Base class.
• The class which derives actually is the Derived class.
• Inheritance can even be Multi-level or Multiple.
• The main advantage we get here is to avoid code redundancy.

?

Runtime Polymorphism

Virtual functions: Now the game is in different types of classes: Base(Parent) class and Derived(child) class. Generally C++ allows the base pointer to point to any object derived from the base class, it cannot directly access the members of the derived class. Thus virtual functions allow the base pointer to access the members of the derived class. Base class virtual function with no definition is known as 'Pure virtual function'.

• A class with at least one pure virtual function is known as ‘Abstract class’.

?References: It is a variable that behaves as an alias for another variable and can be accessed from either of names, and acts as function formal parameters to support pass-by-reference. No need for extra memory for reference, where a pointer requires space for itself.

?Type Inference: Each time we access complex types, lengthy code at programmers end. Why can’t we leave it to the compiler? Yes, It’s the new feature, automatic deduction of type and assignment is achieved through auto, decltype keywords.

Compile time Polymorphism

Function and Operator Overloading: Ability to have two or more functions with the same name but may differ in type or number of arguments. Actual function calls are decided upon context and these functions have capability of performing various tasks.?

• To perform different operations on the same operand in different contexts, operator overloading is used.

Type-safe free-store memory allocation (new/delete): Dynamic memory allocation through malloc(), calloc() and realloc() simply creates a block of memory and returns a void pointer. Advantages of new operator are:

• ?Memory is allocated and returns a pointer of specific type that is being created.
• Automatic constructor call if it is a class object.
• Initializes memory if values are passed.
• Requests for memory allocation on free store. If not available an exception is thrown.

Whereas, delete operator is used just to free the allocated memory and to add it to the free store.

?Protected members: Members of a class can be protected? using access specifiers. C++ has three types: Public, protected and private.

• Visibility of members of a struct or class can be controlled by using them.
• Public: Global scope
• Protected: Limited to this and derived classes
• Private: Limited to this class only.
• Flaw in C++ Member protection: However, friend functions or friend classes can access even the private data members of the class which is being declared.
• Also, note that this relation is only one way.

Static and const Member functions: The data members or methods that have class scope or not specific to any instance can be declared as static members.

‘const’ member functions helpful for const objects which cannot be modified. These objects however should be initialized during creation.

Templates: Templates used for generic programming. Declaring a generic template makes things easy and encourages code reusability.?

• Templates can be created for functions and even for classes.

However, the compiler generates a function or class for a particular template and replaces generic type with passed type.

Exceptions: This is an additional feature added to later versions of C++, enabling better error handling.

• C++ library has a standard exception class. However, all exceptions are unchecked by the compiler.

Standard Template Library: It’s a set of classes for access to inbuilt data structures, containers, iterators and common algorithms. Includes utility library.

?Namespaces: It is a declarative region that provides a scope to the identifiers inside it. Multiple namespace blocks with the same name are allowed. All declarations within those blocks are declared in the named scope.

• For example, standard namespace std has many classes defined in it. Such as, cout, string, cin …
• With using ?construct, we can avoid scope resolution each time.

Disclaimer:

This article is not meant for monetization and written just for community contribution.

Audience: Absolute C++ beginners or undergraduate students.

By?

BOPPANA VENKATESH

April 28, 2022.

References:

1.The Design and Evolution of C++, Bjarne Stroustrup

2.The C++ Programming Language, Bjarne Stroustrup

3. Online resources