C vs. C++: 12 Key Differences and Similarities

1. Working

• After writing a C program, users must run it via a C compiler to generate an executable that the PC can execute.
• The C program is the human-readable form, whereas the executable generated by the compilers is the machine-readable form. This implies that a C compiler is necessary to develop and execute a C program.
• If you are running UNIX, you have access to a free C compiler. It can be either “cc” or “gcc” and can be accessed through the command line.
• The user must obtain an open-source C compiler or buy a commercial compiler if they are using Windows. 

Microsoft’s Visual C++ environment is a widely used business-grade compiler that builds both C and C++ applications.

• The compiler first executes the preprocessor on the source code systems. 
• Second, the compiler creates an object file from the preprocessor’s output.
• The linker feature of the C++ compiler converts the object files generated by the compiler into a fixed or shareable library or executable file.
• Once many source files have been converted into an object file, they may be combined into a common or fixed library or an executable file.

C++ provides extensive library support for conventional or built-in database systems, algorithms, etc., in addition to third-party libraries such as the Boost libraries.

2. Programming style 

C uses modularity and scoping to improve its readability and reduce complexity. Also, it does not support concepts such as polymorphism, inheritance, encapsulation, and abstraction. 

3. Approach to solving logical problems

The solutions to these subproblems are then combined to find the main solution to the problem. In this approach, testing and debugging are much easier and more efficient.

Code written using this approach is reusable and helpful to programmers when adding new features to an application. 

4. Support for function overloading

Function overloading is a type of polymorphism that enhances code readability, saves memory space, and allows code reusability. It also makes the code flexible and speeds up the execution of programs. C is not designed to support function overloading.

5. Use of inheritance

The derived class can have extra features not present in the base class. Inheritance reduces data redundancy by avoiding data duplication and is helpful for code reusability. 

The C language lacks this inheritance feature.

6. The availability of namespace 

The namespace feature is unavailable in C. Programmers can resolve identifier conflicts in C using a standard name prefix for each module. The prefix should indicate the specific location to which the name belongs, enabling the compiler to use the suitable module.

7. Exception handling

C does not support exception handling. However, programmers can implement different error handling techniques, such as incorporating the global variable errno and performing tests on return values to ensure their code has no errors in the first place.

8. Ease of coding

• Its code portability allows programmers to write code on one system and use it in a different system. 
• Its code is easy to learn and understand, requiring no previous technical knowledge. 
• It is a hands-on language that requires developers to tell the software what to do. 
• It only contains 32 keywords. Additionally, it has a clean and concise syntax.

9. Support for operator overloading

In operator overloading, at least a single operand must be a user-defined class object. Programmers use overloaded operators to make programs more intuitive. 

C does not support the operator overloading feature.

10. Data security, encapsulation, and information hiding

In C, global declarations allow data communication between different blocks of code. Thus, it is less secure.

C++ also supports the abstraction feature that allows programmers to only reveal information that the user requires on the interface while hiding the rest of the implementations. This feature is not available in C. 

By supporting both encapsulation and abstraction features, C++ promotes the hiding of information, which enhances data security in programs, unlike C, which does not enhance information hiding. 

11. Memory management

Memory allocation is done during runtime, while deallocation is done when a variable is no longer required. In both languages, memory management is done manually – but with subtle differences. 

In C, malloc() or calloc() functions dynamically allocate memory at run time. The malloc() function is used to create a single block of memory of a specific size, while the calloc() function assigns multiple blocks of memory to a single variable. The free() function is used for memory deallocation.

12. Examples

• The Windows kernel is created primarily in C, with certain assembly language components.
• Adobe Photoshop was developed solely using the C programming language. Additionally, it was used to create Adobe Illustrator as well as Adobe Premiere.
• Numerous Google Open Source projects are maintained using the C programming language.
• Popular games like Google’s Dino and Snake are created in the C programming language.
• MySQL is a C-based, open-source database management system (DBMS) program.

• C++ is a common option for operating system development.
• C++ is commonly used in the development of game engines due to its ability to manage hardware resources and support CPU-intensive operations.
• C++ is used to develop the renderer engines of several web browsers because of its speed.
• Infosys Finacle is among the most widely used core-banking systems employing C++ as its underlying programming language.
• C++ is the principal programming language for several embedded systems, such as medical equipment, smartwatches, internet of things (IoT) devices, etc.