我正在使用Rust完成2020年的编程挑战日历第3天,以便进行一些训练,因为我是Rust的新手,我的代码是否能够编译取决于我在“tree”变量上使用单引号还是双引号。
第一段代码片段将无法编译,并显示错误:expected u8
, found &[u8; 1]
use std::fs;
fn main() {
let text: String = fs::read_to_string("./data/text").unwrap();
let vec: Vec<&str> = text.lines().collect();
let vec_vertical_len = vec.len();
let vec_horizontal_len = vec[0].len();
let mut i_pointer: usize = 0;
let mut j_pointer: usize = 0;
let mut tree_counter: usize = 0;
let tree = b"#";
loop {
i_pointer += 3;
j_pointer += 1;
if j_pointer >= vec_vertical_len {
break;
}
let i_index = i_pointer % vec_horizontal_len;
let character = vec[j_pointer].as_bytes()[i_index];
if character == tree {
tree_counter += 1
}
}
println!("{}", tree_counter);
}
第二个片段编译并给出了正确的答案。
use std::fs;
fn main() {
let text: String = fs::read_to_string("./data/text").unwrap();
let vec: Vec<&str> = text.lines().collect();
let vec_vertical_len = vec.len();
let vec_horizontal_len = vec[0].len();
let mut i_pointer: usize = 0;
let mut j_pointer: usize = 0;
let mut tree_counter: usize = 0;
let tree = b'#';
loop {
i_pointer += 3;
j_pointer += 1;
if j_pointer >= vec_vertical_len {
break;
}
let i_index = i_pointer % vec_horizontal_len;
let character = vec[j_pointer].as_bytes()[i_index];
if character == tree {
tree_counter += 1
}
}
println!("{}", tree_counter);
}
我没有找到任何解释单引号或双引号用法的资料..有人可以帮忙吗?