Open NicolaBernini opened 5 years ago
Functions Syntax
fn
keyword fn func_name(arg: type, ...) -> type
{...}
Example
fn square(num: i32) -> i32
{
return num*num;
}
Rust is a statically type language which means the type of each variable is known at compile time
There are 2 ways to define variable type
Explicitely annotate a variable, using the type annotation syntax as follows
let var_name: type
Letting the compiler infer it (like C++11 auto
)
Variables are by default immutable but can be made mutable by adding mut
specifier in their declaration before their name
let mut var_name: type
Examples
Immutable Variable explicitly annotated but uninitialized (not usable)
let temp: i32;
Immutable Variable explicitly annotated and initialization (usable)
let temp: i32 = 56;
Two stage declaration + initialization equivalent to the above one
let temp: i32;
temp = 56;
Immutable Variable with implicitly deducted type as a result of initialization (usable)
let temp = 32;
Mutable Variable uninitialized
let mut temp: i32;
Mutable Variable initialized
let mut temp: i32 = 56;
Overview
Some Basic Elements about Rust Programming