References and Borrowing
https://doc.rust-lang.org/book/references-and-borrowing.html を途中まで。 特別気になる箇所はなし。
fn main() { fn sum_vec(v: &Vec<i32>) -> i32 { return v.iter().fold(0, |a, &b| a + b); } fn foo(v1: &Vec<i32>, v2: &Vec<i32>) -> i32 { let s1 = sum_vec(v1); let s2 = sum_vec(v2); s1 + s2 } let v1 = vec![1, 2, 3]; let v2 = vec![4, 5, 6]; let answer = foo(&v1, &v2); println!("{}", answer); }