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Memory Layout

How many bytes does a type actually occupy?

The std::mem::size_of::() function helps you inspect the stack size of any type at compile time.

use std::mem;

fn main() {
    println!("i32    : {}", mem::size_of::<i32>());
    println!("u32    : {}", mem::size_of::<u32>());
    println!("f64    : {}", mem::size_of::<f64>());
    println!("char   : {}", mem::size_of::<char>());
    println!("&str   : {}", mem::size_of::<&str>());
    println!("String : {}", mem::size_of::<String>());
}

• Primitive numeric types store values directly.
• &str is a pointer containing a memory address and length.
• String stores metadata on the stack but allocates its text on the heap.

String Literal points to location where Literal values are stored (Static Memory).

fn main(){
    let s = "Rachel";
    println!("{},{:p}", s, s.as_ptr())
}

#memoryVer 2.0.12