18.8 Summary
Rust’s standard library provides a versatile suite of collection types, with Vec<T>, String, and HashMap<K, V> being the most commonly used. These types offer essential capabilities for managing dynamic data whose size isn’t known at compile time.
For C programmers, the paramount advantage is that Rust collections manage their own memory safely and automatically, governed by the ownership and borrowing system. This design fundamentally eliminates entire categories of memory management errors prevalent in C, such as memory leaks, use-after-free, double frees, and buffer overflows associated with manual malloc/realloc/free usage.
These collections provide not only safety but also efficiency, often matching the performance of carefully tuned C implementations while drastically reducing the risk of memory corruption bugs. By understanding the characteristics, performance trade-offs, and typical use cases of Rust’s collections, you can write more expressive, robust, and maintainable code that effectively handles dynamic data, liberating you from the considerable burden and risks of manual memory management in C.