Updated June 2, 2023

Introduction on RUST and C++

Rust is a system-level programming language that anchors on speed, safety, memory, and parallelism. It is syntactically comparable to C++, but it maintains high performance by providing better memory safety. Mozilla produces Rust and has made it open-source, enabling a wide range of developers to utilize it. The developers are using rust up to build various new software applications, such as file systems, game engines, browser components, operating systems, virtual reality simulation engines, etc.

C++ is one of the most accepted programming languages globally, and nowadays, it can be found in most of today’s Graphical User Interfaces, operating systems, games, and embedded systems. C++ uses the object-oriented approach, which gives us a clear view of the programs’ complexity and allows us to reuse our code, resulting in better readability and less economic development costs. Furthermore, C++ offers ease of use and portability, enabling developers to create applications for various platforms like Windows, Linux, UNIX, Mac, and more.

Head to Head differences between Rust and C++(Infographics)

Given below are the top differences between Rust vs C++:

Key Difference between Rust and C++

Both Rust and C++ are popular choices in the market. Let’s discuss some of the major differences:

1. Move semantics

Moving the constructor results in invalid objects with unspecified states, causing errors due to using a moving object. After moving an object in Rust, the static analyzer (built-in) changes its state to unusable. The analyzer (built-in) tags all the optimizations, freeing the compiler from them. Whereas in C++, Errors due to using a moving object can be spotted by static code analyzers (external) at compile time. A special sentinel state is used to detect these errors at runtime.

2. Secure Memory Usage

Check on free variable usage, dangling pointers, etc. In Rust, tools can be used to find raw pointers inside unsafe blocks. Whereas in C++, Raw pointers can only be spotted manually in code review, whereas smart pointers are simple to track.

3. Secure Memory Usage

Null dereferencing errors. In Rust, option types can emulate null references, which need null checks explicitly before use. Smart pointers return optional references; hence they also require explicit checks. Raw pointers can be made null only when used inside unsafe blocks. Whereas in C++, even for smart pointers, null dereferencing is possible; hence it should be avoided since it is considered undefined behaviour. Compiler in C++ will never catch up with warnings or errors on such issues. But compile-time errors can be caught by static code analyzers (external).

4. Secure Memory Usage

Errors are caused due to buffer overflow. Rust automatically enforces range checks on all slice types at runtime. Whereas in C++, range checks can be enforced by wrapper classes which must be explicitly introduced in the code.

5. No data race between Threads

Modification of concurrent data( unsafely ). In Rust, possible inconsistency can be traced by the rust reference model and built-in borrow checker at compile time. Unsafe Misuse of mutexes can be made impossible by locking API unsafely. Whereas in C++, some errors can be spotted by static code analyzers (external) at the time of compilation. Good knowledge, careful review, and programming discipline are necessary for avoiding concurrency errors. Some errors can be spotted by code sanitizers (external) at runtime.

6. Object initialization

Initialization of variables. In Rust, any variable created in Rust Program should be initialized. ( else results in a compiler error). All the types in Rust have some default defined values. Whereas in C++, uninitialized variables can be spotted by static code analyzers (external). If not initialized, objects of any primitive types will result in undefined values.

7. Pattern matching

Handling every branch of a switch statement appropriately is crucial. Neglecting to handle a branch can lead to consequences. Rust guarantees thoroughness by mandating that developers account for every possible value of a pattern. If any value is missing, the code will not compile. Whereas in C++, Each and every possible branch of the switch statement can be spotted by static code analyzers (external) and Code reviews.

8. Static (compile-time) Polymorphism

In some cases, static interfaces are employed to achieve compile-time polymorphism in Rust. In Rust, both the static and dynamic interfaces have been specified in a united way by Traits.During compilation, Rust ensures the resolution of all compile-time polymorphism. Whereas in C++, some compilers may optimize virtual function calls in some known cases. Interfaces are declared using abstract classes and virtual functions.

9. Type Inference

It is tedious to type some of the (complex) variable types manually. In Rust, function declarations require explicit types that ensure good program readability. Inside a function body in Rust, (Local) Type Inference allows us to specify types explicitly less frequently. Whereas in C++, The decltype & auto keywords provide a limited type of type inference ( for the code’s expressions).

10. Macros

In Rust, the Syntax to define macros in Rust is macros_rules!. Whereas in C++, Syntax to define a macros in C++ is #define

11. Standard library

The standard library makes the most of the utility type’s legacy design. In Rust, tuples, enumerations, and structures form some of the built-in structured types of Rust. The standard library fully utilizes all the available pattern matching to provide foolproof Interfaces. Whereas in C++, Ad-hoc structures can replace structured types such as std:: variant, std:: tuple, and std:: pair.

Comparison Table of Rust vs C++

Below is an explanation of the comparison table between Rust vs C++:

Key factors	Rust	C++
Zero overhead abstraction Zero overhead abstraction is a functionality in the source code but does not have any overhead on the compiled object code.	Developers can achieve a zero-overhead abstraction.	It is possible to achieve a zero-overhead abstraction.
Secure Memory Usage Check on free variables usage, dangling pointers, etc.	Smart pointers are the preferred choice over raw pointers.	Smart pointers are the preferred choice over raw pointers.
Secure Memory Usage Null dereferencing errors	It is advisable to use pointers for reference and ensure that they are not null.	Highly recommending the usage of pointers for referencing and the avoidance of null values.
No data race between Threads Modification of concurrent data( unsafely )	It can result in deadlocks.	It can result in deadlocks.
Runtime environment Bare-metal or embedded programming imposes high restrictions on runtime.	• Rust directly compiles the program into machine language, making its runtime reasonably low and not supporting garbage collection. • Programs in C++ can be made (without standard libraries) by turning off the range checks, etc.	• C++ directly compiles the program into machine language, making its runtime reasonably low and not supporting garbage collection. • Programs in C++ can be made (without using standard libraries) by dynamic type info, disabled exceptions, etc.
Efficient C bindings Usage of existing libraries of C or any other language.	• Requires wrappers for libraries in other languages. • Exporting a C interface requires including a simple extern declaration. • No overhead while calling C functions in Rust.	• Requires wrappers for libraries in other languages. • To export a C interface, it is necessary to include a simple extern declaration. • No overhead while calling C functions in C++.

Conclusion

Rust is a modern-day new programming language with a similar coding structure to C++, but it is faster and more secure with simple built-in methods.

Quiz Result
Total Questions	Correct Answers	Wrong Answers	Percentage