refactor: make some quality improvements

src/day01.rs

@@ -1,9 +1,5 @@
-use crate::utils;
-
 pub fn execute_task01(content: &str) {
-    let binding = utils::convert_to_string_slice(content);
-    let iter =binding
-        .iter()
+    let iter = content.lines()
         .map(|line| line.to_string());
     let calibration = sum_lines(iter);
 
@@ -13,11 +9,9 @@ pub fn execute_task01(content: &str) {
 
 
 pub fn execute_task02(content: &str) {
-    let binding = utils::convert_to_string_slice(content);
-    let iter = binding
-        .iter()
+    let iter = content.lines()
         .map(|line| {
-            let mut full_str = "".to_owned();
+            let mut full_str = String::new();
             for char in line.chars() {
                 full_str.push(char);
 
@@ -47,17 +41,10 @@ pub fn execute_task02(content: &str) {
 }
 
 fn sum_lines(iter: impl Iterator<Item=String>) -> i32 {
-    iter.map(|line|
-        line
-            .chars()
-            .filter(|char| {
-                match char {
-                    '0'..='9' => true,
-                    _ => false
-                }
-            })
-            .collect::<String>())
-        .map(|number_str| format!("{}{}", number_str.chars().next().unwrap(), number_str.chars().last().unwrap()))
-        .map(|number_str| number_str.parse::<i32>().unwrap())
-        .sum()
+    iter
+    .map(|line| format!("{}{}",
+                        line.matches(|c: char| c.is_ascii_digit()).next().unwrap(),
+                        line.rmatches(|c: char| c.is_ascii_digit()).next().unwrap()))
+    .map(|number_str| number_str.parse::<i32>().unwrap())
+    .sum()
 }

src/main.rs

@@ -6,4 +6,5 @@ const CONTENT01: &'static str = include_str!("input/day01/input.txt");
 fn main() {
     day01::execute_task01(CONTENT01);
     day01::execute_task02(CONTENT01);
+    println!();
 }

src/utils.rs

@@ -1,5 +1,6 @@
 
 
+#[allow(dead_code)]
 pub fn convert_to_string_slice(content: &str) -> Vec<&str> {
     content.lines().collect()
 }