PKMS

Rust crux

2 min read

crux_index

Rust → statically typed (knows types of all variables at compile time) shadowing → reusing same variable Integers

  • isize, usize → 64 or 32 depends on computer architecture
  • has Ordering trait

When you’re compiling in release mode with the --release flag, Rust does not include checks for integer overflow that cause panics. Instead, if overflow occurs, Rust performs two’s complement wrapping. In short, values greater than the maximum value the type can hold “wrap around” to the minimum of the values the type can hold. In the case of a u8, the value 256 becomes 0, the value 257 becomes 1, and so on.

Boolean → 1 byte in size Char → 4 byte in size

Tuple

  • compound type → (int, bool, string ...)
  • unit type → () → for example Ok(())

Statement → returns nothing Expression → returns a value

Expression + ”;” → Statement

(1..n).rev() → reverse iterator

string literals → static memory → stack allocated → cant be changed

vector literals → macros vec![] → this expands to normal heap allocation

Ownership

  • each value has a owner
  • one owner at a time
  • if owner goes out of scope value is dropped

double free error → rust uses “move” operation, so passing variable to a function changes its owner → transfer ownership → there no double free error

passing variables is shallow copy for deep copy use clone

Borrowing

  • at any point in code, a variable can have:
    • one mutable reference
    • infinite immutable reference

impl block

  • associated functions → have self as parameter → :: is used to call them
  • method → does not have self as parameter → .method() is used to call them

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