Should I Focus on C++ or Start Learning Rust?

You don't really have to choose. Learn C++ well enough to understand systems programming and the large amount of existing software built with it, then add Rust afterward. Once you understand programming fundamentals, algorithms, memory, and debugging, picking up another language becomes much easier.

Rust is worth learning because its ownership and borrowing model teaches you to think carefully about resource management, and its tooling and error handling are modern. Just don't treat it as a complete replacement for learning good engineering practices—Rust can still contain logic bugs, unsafe code, and memory leaks through things like reference cycles.

For a 15-year career, don't optimize around guessing which language will win. Focus on data structures, algorithms, operating systems, networking, hardware basics, and building increasingly complex projects. Those skills transfer between languages, and employers usually expect engineers to learn new tools as needed. C++ is not disappearing, and Rust is established enough to be useful, so learning both is a safe choice.

For a job today, C++ generally offers more opportunities because it's used across game development, browsers, finance, operating systems, and legacy systems. Rust is growing and is a great choice for new systems software, but the number of Rust positions is still much smaller. A practical approach is to build your main experience in C++ and study Rust on the side.

If C++ is currently the language you know, go deeper before jumping around. Learn modern C++ rather than relying on outdated techniques, including RAII, smart pointers, standard containers, and good testing practices. Then try Rust with a small project; comparing the two will teach you more than treating them as competing camps.