concepts: rustfmt

[learn-rust.git] / src / main.rs

diff --git a/src/main.rs b/src/main.rs
deleted file mode 100644 (file)
index 0ef1b16..0000000
--- a/src/main.rs
+++ /dev/null
@@ -1,167 +0,0 @@
-mod word_utils;
-mod lib;
-
-use std::collections::HashMap;
-use std::io::{prelude::*, ErrorKind};
-use std::fs::{self, File};
-
-use lib::*;
-use word_utils::{first_word, second_word};
-
-fn test_strings() {
-    let s = String::from("Hello world");
-    println!("first word: '{}'", first_word(&s));
-    println!("second word: '{}'", second_word(&s).unwrap());
-
-    let s2 = "hello dude blah";
-    println!("second word of single: '{}'", second_word(s2).unwrap_or("(none)"));
-
-    match second_word(s2) {
-        Some(w) => println!("match: second word of '{}' exists: {}", s2, w),
-        None => println!("match: second word of '{}' does not exist", s2),
-    }
-}
-
-fn test_vectors() {
-    let v1 = vec![1, 2, 3];
-    println!("statically initialized vector: {:?}", v1);
-
-    let mut v2: Vec<String> = Vec::new();
-    v2.push("Hello".to_string());
-    v2.push(String::from("world"));
-    println!("dynamically built vector: {:?}", v2);
-    println!("first element: {}", v2[0]);
-    for el in &mut v2 {
-        *el += "xx";
-    }
-    for el in &v2 {
-        println!("{}", el);
-    }
-}
-
-fn test_hashmaps() {
-    let mut scores = HashMap::new();
-    scores.insert("john", 10);
-    scores.insert("mary", 20);
-
-    println!("scores: {:?}", scores);
-
-    // hash map with .collect()
-    let persons = vec![("homer", 42), ("marge", 30)];
-    let collect_scores: HashMap<_, _> = persons.into_iter().collect();
-    println!("collect_scores: {:?}", collect_scores);
-
-    for (p, s) in &collect_scores {
-        println!("person {}: score {}", p, s);
-    }
-
-    println!("john's score: {}", scores.get("john").unwrap());
-    println!("jake's score: {}", scores.get("jake").unwrap_or(&-1));
-
-    // double scores
-    for (_, v) in scores.iter_mut() {
-        *v *= 2;
-    }
-    println!("scores after doubling: {:?}", scores);
-
-    // double scores of immutable hashmap (rebuild it)
-    let collect_scores: HashMap<_, _> = collect_scores.iter()
-        .map(|(k, v)| (k, 2 * v))
-        .collect();
-    println!("collect_scores after rebuilding with doubling: {:?}", collect_scores);
-}
-
-fn test_files() {
-    if let Ok(mut f) = File::open("Cargo.toml") {
-        let mut contents = String::new();
-        match f.read_to_string(&mut contents) {
-            Ok(len) => println!("successfully opened Cargo.toml: {:?}, contents {} bytes:\n{}\n----------", f, len, contents),
-            Err(e) => panic!("could not read file: {:?}", e)
-        }
-    } else {
-        println!("could not open Cargo.toml");
-    }
-
-    // alternative form, more specific error checking
-    let mut f = File::open("Cargo.toml").unwrap_or_else(|e| {
-        if e.kind() == ErrorKind::NotFound {
-            println!("Cargo.toml not found, falling back to /dev/null");
-            // need to return a File
-            File::open("/dev/null").unwrap()
-        } else {
-            panic!("Could not open Cargo.toml: {:?}", e);
-        }
-    });
-    let mut contents = String::new();
-    let len = f.read_to_string(&mut contents).unwrap_or_else(|e| {
-        panic!("Could not read file: {:?}", e);
-    });
-    println!("successfully opened Cargo.toml with unwrap_or_else: {:?}, contents {} bytes:\n{}\n----------", f, len, contents);
-
-    // using the '?' operator
-    match read_file("Cargo.toml") {
-        Ok(s) => println!("Cargo.toml contents:\n{}\n-------------", s),
-        Err(e) => println!("Could not open Cargo.toml: {:?}", e)
-    }
-
-    // using std API
-    match fs::read_to_string("Cargo.toml") {
-        Ok(s) => println!("Cargo.toml contents:\n{}\n-------------", s),
-        Err(e) => println!("Could not open Cargo.toml: {:?}", e)
-    }
-}
-
-fn test_generics() {
-    let num_list = vec![3, 42, -7, 100, 0];
-    println!("largest number: {}", largest(&num_list));
-    println!("num_list: {:?}", num_list);
-
-    let char_list = vec!['a', 'y', 'q', 'm'];
-    println!("largest char: {}", largest(&char_list));
-
-    let str_list = vec!["hello", "world", "blue", "planet"];
-    println!("largest str: {}", largest(&str_list));
-    println!("str_list: {:?}", str_list);
-
-    let string_list = vec!["aaaa".to_string(), "xxxxx".to_string(), "ffff".to_string()];
-    println!("largest string (with cloning): {}", largest_clone(&string_list));
-    println!("largest string (with ref): {}", largest_ref(&string_list));
-    println!("string_list: {:?}", string_list);
-
-    let s1 = String::from("abcd");
-    let l;
-    {
-        let s2 = "efghi";
-        l = longest(&s1, s2);
-    }
-    println!("longest string: {}", l);
-}
-
-fn test_closures() {
-    let mut expensive_int_result = Cacher::new(|x| {
-        println!("calculating expensive int result for {}", x);
-        2 * x
-    });
-
-    println!("1st int call for value 1: {}", expensive_int_result.value(1));
-    println!("2nd int call for value 1: {}", expensive_int_result.value(1));
-    println!("1st int call for value 2: {}", expensive_int_result.value(2));
-
-    let mut expensive_str_result = Cacher::new(|x: &str| {
-        println!("calculating expensive str result for {}", x);
-        x.len()
-    });
-
-    println!("1st int call for value abc: {}", expensive_str_result.value("abc"));
-    println!("2nd int call for value abc: {}", expensive_str_result.value("abc"));
-    println!("1st int call for value defg: {}", expensive_str_result.value("defg"));
-}
-
-fn main() {
-    test_strings();
-    test_vectors();
-    test_hashmaps();
-    test_files();
-    test_generics();
-    test_closures();
-}