Difference Between C and C++

Given below is the difference between the C and C++ languages:

Aspect	C Programming Language	C++ Programming Language
OOPs Support	As C is a procedural-oriented programming language, it does not support OOPs concepts.	C++ is an object-oriented programming language, and hence it supports the OOPs concept, which has polymorphism, inheritance, abstraction, and encapsulation.
Keywords	Number of keywords in C: – C90: 32 – C99: 37 – C11: 44 – C23: 59	Number of keywords in C++: – C++98: 63 – C++11: 73 – C++17: 73 – C++20: 81
File Extensions	The file extension for the C programming language is “.c”.	The file extension for the C++ programming language is “.cpp” or “.c++” or “.cc” or “.cxx”.
Header File	The header file use in C language is <stdio.h>	The header file use in C++ language is <iostream>
Input/Output Functions	The input function used in the C language is “scanf()”, and the output function uses “printf()”.	The input function used in the C++ language is “cin”, and the output function used is “cout”.
Data Hiding	The C program does not support data hiding.	The C++ program has a data-hiding feature, which is encapsulation, to ensure that the data structures and operators are used as intended.
Virtual Functions	The C language does not support virtual and friend functions, as it is a procedural language.	C++ supports virtual functions (enables runtime polymorphism using base-class pointers) and friend functions (which allow external functions or classes to access private data).
Access Modifiers	The C language does not have access specifiers, as in the C language the structures are purely data containers and it does not support access specifiers.	The C++ language has access specifiers (like public, private, and protected).
Focus of Language	The C language is a function-driven language, as it is a procedural programming language, and the program logic is built around functions to improve readability and maintainability.	The C++ language is an object-driven language, as it is based on the concept of objects and classes, which allows the data and functions to be bundled together, enabling modular, reusable, and scalable code.
Exception Handling	The C programming language does not have built-in support for exception handling.	The C++ programming language has built-in support for exception handling (three primary keywords are try, throw, and catch).
Namespace	The namespace is not supported in the C language, as it is a procedural language, and its global scope is flat, due to which all the global functions and variables share the same namespace.	The namespace is supported by the C++ programming language. which helps to organize the codes and avoid name collisions by grouping identifiers under a unique name.
Type Punning with Unions	The C programming language allows type punning through unions in C99 and later.	The C++ language has strict rules about object lifetimes and type aliasing, and hence type punning with unions is an undefined behavior, except in very specific circumstances.
Generic Programming	The C language allows basic meta-programming through macros and the _Generic().	The meta-programming is supported by the C++ language at compile time using templates, which makes it type-safer.
Dynamic Memory	For dynamic allocation, the C language provides malloc(). and calloc(). for memory deallocation.	For dynamic allocation of memory in C++ language, it provides two operators: new, for memory allocation, and delete, for memory deallocation.
Type Checking	The C language provides more flexible and less strict type checking, which can sometimes lead to unsafe operations or subtle bugs.	The C++ language provides strict checking at compile time, which helps to catch many bugs early in the development process.

C vs C++: Which One Should You Use and When?

Here is a table in which we have discussed a few use cases, along with the reasons when and why you should use the C language for those cases:

Use Case	Reason for choosing C language
System Programming	C is optimal for operating systems, device drivers, and kernels (like Linux) as it provides low-level access to memory and system processes with less abstraction.
Performance Critical Tasks	There is no overhead from object-oriented mechanisms, so the C language has no virtual tables, abstractions, or inheritance, and also the code is translated almost directly into machine-level language by the compiler. So, C generates fast.
Small, Resource-constrained Devices	As C has minimal runtime, efficient memory usage, and close-to-hardware capabilities, it works well on microcontrollers and embedded systems.
Learning Low-Level Concepts	We can easily understand low-level programming concepts like memory management, stack/heap allocation, and pointers if we learn the C language.

Now, let’s look at another table that shows when and why you should use C++ :

Use Case	Reason for using C++ language
Software Requiring Reusability and Scalability	The object-oriented features like objects, classes, encapsulation, inheritance, abstraction, and polymorphism allow the developers to write modular, organized, and extensible code, which makes it easier to manage and scale larger codebases. This is the reason that C++ is ideal for building the software that requires reusability and scalability.
Large-Scale Applications	As C++ is an object-oriented programming language, it has features like classes, objects, encapsulation, and inheritance, which promote better code structure, modularity, and reusability, which makes it easier to manage, extend, and maintain the complex systems over time. Due to which C++ is well-suited for large-scale applications.
Competitive Programming	C++ is mostly chosen for competitive programming because of the STL (Standard Template Library), which provides powerful, ready-to-use data structures and algorithms.
Modern Development Needs	The modern software development need is satisfied by the C++ language through features like exception handling, templates, namespaces, operator overloading, and many more. These features help the developers to write maintainable, reusable, and robust code.

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Companies using C and C++

Due to the high performance and low memory usage, a list of companies uses the C language, including:

Bosch
Microsoft
Oracle
IBM
Intel

Due to the object-oriented features, a list of companies use the C++ language, including

Autodesk
Amazon
Google
Adobe
Facebook (Meta)
Siemens.

Similarities Between C and C++

The below is a list that shows the similarities between C and C++ :

Compilation: Both C and C++ are compiled languages, which means that both are first converted into machine code before they are executed.
Support for Pointers: Both C and C++ support function pointers that allow functions to be passed as arguments to other functions.
Variable grouping: Both C and C++ support structures, which are user-defined data types that allow us to group related variables of different types under a single name.
File input/output: C and C++ support file input/output using similar basic functions to create, open, and close files.
Basic Functions: C and C++ use similar basic functions; for instance, library functions such as printf() and fgets().

Code Example for C

Let’s take some examples of the C programming language:

Example 1: C Program to Add Two Numbers using Functions

In this program, we will see how to add two numbers using the functions. A function is a self-contained block of code that performs a part task when called.

Output:

Example 2: C Program to Show How to Use the Structure

In this program, we will see how to use the structures in the C language. A structure is a user-defined data type that allows us to group related variables under a single name.

Output:

Example 3: C Program to Show How Pointers Are Used

This program shows us how to use pointers in the C language. A pointer is a variable that stores the memory address of another variable.

Output:

Code Example for C++

Let’s take some examples of the C++ programming language:

Example 1: C++ Program to Add Two Strings (Concatenation) using Functions

This program shows how to add two strings using functions. The process of adding two or more strings is called concatenation.

Cpp

Output:

Example 2: C++ Program to Show How to Use a Pointer

This program shows how to use a pointer in the C++ language.

Cpp

Output:

Example 3: C++ Program to Calculate the String Length and Show the Substring

This program shows how to calculate the string length and show the substring.

Cpp

Output:

C++ program to calculate string length and substring

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Conclusion

With this, we have learned the difference between C and C++, which are foundational programming languages and share many concepts but have different significance in their capabilities and use cases. Use C for better performance and low-level access, whereas use C++ for making the code scalable, maintainable, and reusable.

Difference between C and C++ – FAQs

1. What is the main difference between C and C++?

C is a procedural programming language, while C++ is an object-oriented language that supports classes, objects, abstraction, encapsulation, polymorphism, and inheritance.

2. Is it better to learn C or C++?

C is a low-level language and uses less memory, while C++ is a high-level language that breaks the complex code into smaller parts. It depends on the programmer which one to use according to their need.

3. Which is faster, C or C++?

Both C and C++ are faster, but comparatively, C is considered faster in practice for a few reasons. The reason is that it has minimal abstraction, smaller runtime, and tighter control over memory.

4. Which is harder, C or C++?

Generally, C is considered easier to learn, especially for beginners, as it has simple syntax with no classes, abstraction, or inheritance. On the other hand, C++ is easier to use in large-scale software because of its powerful feature OOPs, which makes the code scalable, maintainable, and reusable.

5. What is OOPs in C++?

In C++, OOP is an object-oriented programming language. It is a programming paradigm supported by C++ that is based on the concept of objects and classes, which helps to make the code more maintainable and scalable.