More exercises

.gitignore

@@ -5,3 +5,5 @@ target/
 *.pdb
 exercises/clippy/Cargo.toml
 exercises/clippy/Cargo.lock
+
+.idea

exercises/clippy/clippy1.rs

@@ -4,12 +4,11 @@
 //
 // Execute `rustlings hint clippy1` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let x = 1.2331f64;
     let y = 1.2332f64;
-    if y != x {
+    if (y - x).abs() > 0.0001 {
         println!("Success!");
     }
 }

exercises/clippy/clippy2.rs

@@ -1,12 +1,11 @@
 // clippy2.rs
 // Make me compile! Execute `rustlings hint clippy2` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let mut res = 42;
     let option = Some(12);
-    for x in option {
+    if let Some(x) = option {
         res += x;
     }
     println!("{}", res);

exercises/error_handling/errors1.rs

@@ -6,14 +6,13 @@
 // this function to have.
 // Execute `rustlings hint errors1` for hints!
 
-// I AM NOT DONE
 
-pub fn generate_nametag_text(name: String) -> Option<String> {
+pub fn generate_nametag_text(name: String) -> Result<String, String> {
     if name.len() > 0 {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     } else {
         // Empty names aren't allowed.
-        None
+        Err("`name` was empty; it must be nonempty.".to_string())
     }
 }
 
@@ -28,7 +27,7 @@ mod tests {
     fn generates_nametag_text_for_a_nonempty_name() {
         assert_eq!(
             generate_nametag_text("Beyoncé".into()),
-            Some("Hi! My name is Beyoncé".into())
+            Ok("Hi! My name is Beyoncé".into())
         );
     }
 

exercises/error_handling/errors2.rs

@@ -16,14 +16,13 @@
 // There are at least two ways to implement this that are both correct-- but
 // one is a lot shorter! Execute `rustlings hint errors2` for hints to both ways.
 
-// I AM NOT DONE
 
 use std::num::ParseIntError;
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
-    let qty = item_quantity.parse::<i32>();
+    let qty = item_quantity.parse::<i32>()?;
 
     Ok(qty * cost_per_item + processing_fee)
 }

exercises/error_handling/errors3.rs

@@ -4,11 +4,10 @@
 // Why not? What should we do to fix it?
 // Execute `rustlings hint errors3` for hints!
 
-// I AM NOT DONE
 
 use std::num::ParseIntError;
 
-fn main() {
+fn main() -> Result<(), ParseIntError> {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -20,6 +19,8 @@ fn main() {
         tokens -= cost;
         println!("You now have {} tokens.", tokens);
     }
+
+    Ok(())
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {

exercises/error_handling/errorsn.rs

@@ -15,19 +15,18 @@
 //
 // Execute `rustlings hint errorsn` for hints :)
 
-// I AM NOT DONE
 
 use std::error;
 use std::fmt;
 use std::io;
 
 // PositiveNonzeroInteger is a struct defined below the tests.
-fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger, ???> {
+fn read_and_validate(b: &mut dyn io::BufRead) -> Result<PositiveNonzeroInteger, Box<dyn error::Error>> {
     let mut line = String::new();
-    b.read_line(&mut line);
+    b.read_line(&mut line)?;
-    let num: i64 = line.trim().parse();
+    let num: i64 = line.trim().parse()?;
-    let answer = PositiveNonzeroInteger::new(num);
+    let answer: PositiveNonzeroInteger  = PositiveNonzeroInteger::new(num)?;
-    answer
+    Ok(answer)
 }
 
 // This is a test helper function that turns a &str into a BufReader.

exercises/error_handling/option1.rs

@@ -12,7 +12,10 @@ pub fn pop_too_much() -> bool {
     let last = list.pop().unwrap();
     println!("The last item in the list is {:?}", last);
 
-    let second_to_last = list.pop().unwrap();
+    let second_to_last = match list.pop() {
+        Some(i) => i,
+        None => 0
+    };
     println!(
         "The second-to-last item in the list is {:?}",
         second_to_last

exercises/error_handling/result1.rs

@@ -1,7 +1,6 @@
 // result1.rs
 // Make this test pass! Execute `rustlings hint result1` for hints :)
 
-// I AM NOT DONE
 
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
@@ -14,7 +13,13 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        Ok(PositiveNonzeroInteger(value as u64))
+        if value == 0 {
+            Err(CreationError::Zero)
+        } else if value < 0 {
+            Err(CreationError::Negative)
+        } else {
+            Ok(PositiveNonzeroInteger(value as u64))
+        }
     }
 }
 

exercises/option/option1.rs

@@ -1,7 +1,6 @@
 // option1.rs
 // Make me compile! Execute `rustlings hint option1` for hints
 
-// I AM NOT DONE
 
 // you can modify anything EXCEPT for this function's sig
 fn print_number(maybe_number: Option<u16>) {
@@ -9,15 +8,15 @@ fn print_number(maybe_number: Option<u16>) {
 }
 
 fn main() {
-    print_number(13);
+    print_number(Some(13));
-    print_number(99);
+    print_number(Some(99));
 
-    let mut numbers: [Option<u16>; 5];
+    let mut numbers: [Option<u16>; 5] = [None; 5];
     for iter in 0..5 {
         let number_to_add: u16 = {
             ((iter * 5) + 2) / (4 * 16)
         };
 
-        numbers[iter] = number_to_add;
+        numbers[iter as usize] = Some(number_to_add);
     }
 }

exercises/option/option2.rs

@@ -1,12 +1,11 @@
 // option2.rs
 // Make me compile! Execute `rustlings hint option2` for hints
 
-// I AM NOT DONE
 
 fn main() {
     let optional_value = Some(String::from("rustlings"));
     // Make this an if let statement whose value is "Some" type
-    value = optional_value {
+    if let Some(value) = optional_value {
         println!("the value of optional value is: {}", value);
     } else {
         println!("The optional value doesn't contain anything!");
@@ -19,7 +18,7 @@ fn main() {
 
     // make this a while let statement - remember that vector.pop also adds another layer of Option<T>
     // You can stack `Option<T>`'s into while let and if let
-    value = optional_values_vec.pop() {
+    while let Some(Some(value)) = optional_values_vec.pop() {
         println!("current value: {}", value);
     }
 }