9.1 Introduction to Structs and Comparison with C

Structs in Rust let developers define custom data types by grouping related values together. This concept is similar to the struct type in C. Unlike Rust tuples, which group values without naming individual fields, most Rust structs explicitly name each field, enhancing both readability and maintainability. However, Rust also supports tuple structs, which behave like tuples but provide a distinct type—these will be discussed later in the chapter.

A basic example of a named-field struct in Rust:

struct Person {
    name: String,
    age: u8,
}

For comparison, a similar definition in C might be:

struct Person {
    char* name;
    uint8_t age;
};

While both languages group related data, Rust expands on this concept significantly:

  • Explicit Naming: Rust requires structs to be named. Most Rust structs have named fields, but tuple structs omit field names while still offering a distinct type.
  • Memory Safety and Ownership: Rust ensures memory safety with strict ownership and borrowing rules, preventing common memory errors such as dangling pointers or memory leaks.
  • Methods and Behavior: Rust structs can have associated methods, defined separately in an impl block. C structs cannot hold methods directly, so functions must be defined externally.

Rust structs also serve a role similar to OOP classes but without inheritance. Data (struct fields) and behavior (methods) are kept separate, promoting clearer, safer, and more maintainable code.