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This post is auto-generated from RSS feed The Rust Programming Language Forum - Latest topics. Source: A bit confused what a variable is

Just following this example from the interactive book:

fn main() {
let mut x: Box<i32> = Box::new(1);
let a: i32 = *x;         // *x reads the heap value, so a = 1
*x += 1;                 // *x on the left-side modifies the heap value,
                         //     so x points to the value 2

let r1: &Box<i32> = &x;  // r1 points to x on the stack
let b: i32 = **r1;       // two dereferences get us to the heap value

let r2: &i32 = &*x;      // r2 points to the heap value directly
let c: i32 = *r2;    // so only one dereference is needed to read it
}

* is "clicking" on a reference, following a heap pointer to the value. And also allows updating in this case. From that, one would say x is simply the reference.

x is the variable that binds the instance of Box<i32>, which is located in the stack, but it has some properties etc., and a heap pointer to the numeric result (the i32 value).

• So is x just a reference that leads to its value when de-referenced, or what would be a good way to think about it (for a person newly introduced to Rust)?

• Or should I think of x as a pointer to the start of the item in the stack? Or is x a Stack address?

• Or what?

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