Rust Vs. C++: Key Differences for Experienced Developers

As an experienced C++ developer, you’ve likely heard the buzz around Rust. While both languages target similar domains—system programming, performance critical applications, and embedded systems—they approach many fundamental concepts differently. This blog explores the key differences that matter the most to seasoned C++ developer considering Rust.

Memory safety philosophy

C++ gives you power with responsibility. You manage memory manually, deciding when to allocate and deallocate resources. This freedom provides precise control but opens the door to common bugs like dangling pointers, memory leaks and use-after-free errors.

Rust takes a different approach with its ownership system. The compiler enforces strict rules about the memory management at compile time, effectively preventing entire classes of bugs.

What C++ accomplishes with careful programmer discipline, Rust achieves through compiler enforcement.

// Rust example - compiler prevents use-after-free
let s1 = String::from("hello");
let s2 = s1;    // s1 is moved here and no longer valid
// println!("{}", s1);     // this would cause compiler error

No Null Pointers

C++’s nullptr has been called a “billion dollar mistake”. Rust eliminates null pointer dereferencing with its Option<T> type, forcing explicit handling of potentially absent values:

// Rust's approach to nullable values
let name: Option<String> = Some(String::from("Alice"));
match name {
      Some(n) => println!("Name: {}", n),
      None => println!("No name provided"),
}

Immutability by default

In C++, variables are mutable unless declared const . Rust flips this paradigm—everything is immutable by default unless marked mut. This significantly reduces bugs related to unexpected state changes.

Concurrency Without Fear

C++ gives you threads and synchronization primitives but leaves correctness up to to you. Data races are runtime bugs that can be notoriously difficult to reproduce and fix.

Rust’s ownership system extends to concurrency, making data races compile-time errors rather than runtime bugs. The compiler can detect when you’re sharing mutable state between threads without proper synchronization. (Send and Sync traits)

Modern Package Management

While C++ has made strides with tools like Conan and vcpkg, Rust’s Cargo provides a standardized, built-in solution for dependency management, building, testing and documentation generation.

Interoperability with C++

For teams with existing C++ codebases, Rust offers excellent C FFI support. Libraries like cxx facilitate smoother integration between Rust and C++, allowing incremental adoption.

Conclusion

Rust isn’t merely “a better C++” but rather a language with different trade-offs and priorities. Its primary innovation is moving memory and thread safety checks from runtime (or developer discipline) to compile time, while maintaining performance comparable to C++.

For experienced C++ developers, the learning curve may be steep initially, but many report that once they “get” Rust’s ownership model, they find themselves writing more robust code with fewer bugs—even when they return to C++.