Rust study : array and slices.

array_slice.rs

/*
The rust by example ko https://hanbum.gitbooks.io/rustbyexample/content/primitives/array.html
compiled on https://play.rust-lang.org/
result:

Standard Error
   Compiling playground v0.0.1 (/playground)
    Finished dev [unoptimized + debuginfo] target(s) in 1.09s
     Running `target/debug/playground`
thread 'main' panicked at 'index out of bounds: the len is 4 but the index is 5', src/main.rs:17:34
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
Standard Output
first element of the array: 1
second element of the array: 2
size of xs : 5
array occupies 20 bytes
borrow the whole array as a slice
first element of the slice: 1
the slice has 5 elements
borrow a section of the array as a slice
first element of the slice: 0
the slice has 3 elements
*/

use std::mem;

fn analyze_slice(slice: &[i32])
{
    println!("first element of the slice: {}", slice[0]);
    println!("the slice has {} elements", slice.len());
}

fn panic_slice(slice: &[i32])
{
    println!("panice slice! {}", slice[5]);
}

fn main()
{
    let xs: [i32; 5] = [ 1,2,3,4,5 ];
    let ys: [i32; 500] = [0; 500];
    
    println!("first element of the array: {}", xs[0]);
    println!("second element of the array: {}", xs[1]);

    
    println!("size of xs : {}", xs.len());
    
    // 배열은 스택에 할당된다.
    println!("array occupies {} bytes", mem::size_of_val(&xs));
    
    println!("borrow the whole array as a slice");
    analyze_slice(&xs);
    
    println!("borrow a section of the array as a slice");
    analyze_slice(&ys[1 .. 4]);
    
    panic_slice(&xs[1 .. 5]);
}