fn main() {
let fixed=[1_i64,2,3,4]; let grow=vec![0_i64,1,4,9,16];
fn total(xs: &[i64]) -> i64 { xs.iter().sum() }
total(&fixed);
total(&grow);
total(&grow[1..4]);
total(&grow[grow.len() - 2..]);

assert_eq!(total(&fixed),10); assert_eq!(total(&grow),30);assert_eq!(total(&grow[1..4]),14);assert_eq!(total(&grow[grow.len()-2..]),25);
}