rustlings 80 done

exercises/error_handling/errors1.rs

@@ -9,14 +9,13 @@
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a
 // hint.
 
-// 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.is_empty() {
         // Empty names aren't allowed.
-        None
+        Err(format!("`name` was empty; it must be nonempty."))
     } else {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     }
 }
 

exercises/error_handling/errors2.rs

@@ -19,16 +19,20 @@
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a
 // hint.
 
-// 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>();
+    match qty {
+        Ok(qty) => Ok(qty * cost_per_item + processing_fee),
+        Err(e) => Err(e),
+    }*/
+    let qty = item_quantity.parse::<i32>()?;
     Ok(qty * cost_per_item + processing_fee)
+
 }
 
 #[cfg(test)]
@@ -38,7 +42,7 @@ mod tests {
     #[test]
     fn item_quantity_is_a_valid_number() {
         assert_eq!(total_cost("34"), Ok(171));
-    }
+   }
 
     #[test]
     fn item_quantity_is_an_invalid_number() {

exercises/error_handling/errors3.rs

@@ -7,11 +7,10 @@
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::num::ParseIntError;
 
-fn main() {
+fn main() -> Result<(), ParseIntError> {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -23,6 +22,7 @@ fn main() {
         tokens -= cost;
         println!("You now have {} tokens.", tokens);
     }
+    Ok(())
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {

exercises/error_handling/errors4.rs

@@ -3,7 +3,6 @@
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
@@ -17,7 +16,18 @@ enum CreationError {
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
         // Hmm...? Why is this only returning an Ok value?
-        Ok(PositiveNonzeroInteger(value as u64))
+        /*if value > 0 {
+            Ok(PositiveNonzeroInteger(value as u64))
+        } else if (value < 0) {
+            Err(CreationError::Negative)
+        } else {
+            Err(CreationError::Zero)
+        }*/
+        match value {
+            n if n > 0 => Ok(PositiveNonzeroInteger(value as u64)),
+            n if n < 0 => Err(CreationError::Negative),
+            _ => Err(CreationError::Zero),
+        }
     }
 }
 

exercises/error_handling/errors5.rs

@@ -22,14 +22,13 @@
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::error;
 use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), Box<dyn ???>> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);

exercises/error_handling/errors6.rs

@@ -9,7 +9,6 @@
 // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::num::ParseIntError;
 
@@ -24,15 +23,33 @@ impl ParsePosNonzeroError {
     fn from_creation(err: CreationError) -> ParsePosNonzeroError {
         ParsePosNonzeroError::Creation(err)
     }
-    // TODO: add another error conversion function here.
-    // fn from_parseint...
+    fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::ParseInt(err)
+    }
 }
 
 fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
     // TODO: change this to return an appropriate error instead of panicking
     // when `parse()` returns an error.
-    let x: i64 = s.parse().unwrap();
+    // complex way
+    /*
+    let x : i64  = match s.parse() {
+        Ok(n) => n,
+        Err(err) => return Err(ParsePosNonzeroError::from_parseint(err)),
+    };
+    match PositiveNonzeroInteger::new(x) {
+        Ok(n) => Ok(n),
+        Err(err) => Err(ParsePosNonzeroError::from_creation(err)),
+    }
+    */
+    // ?
+    let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
+    PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
+    // use closure fail to compile!!!!
+    /*
+    let x : i64 = s.parse().unwrap_or_else(|err| return Err(ParsePosNonzeroError::from_parseint(err)))?;
     PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
+    */
 }
 
 // Don't change anything below this line.

exercises/functions/functions3.rs

@@ -5,7 +5,7 @@
 
 
 fn main() {
-    call_me(10000000);
+    call_me(1);
 }
 
 fn call_me(num: u32) {

exercises/generics/generics1.rs

@@ -6,9 +6,8 @@
 // Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }

exercises/generics/generics2.rs

@@ -6,14 +6,13 @@
 // Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-struct Wrapper {
-    value: u32,
+struct Wrapper<T> {
+    value: T,
 }
 
-impl Wrapper {
-    pub fn new(value: u32) -> Self {
+impl<T> Wrapper<T> {
+    pub fn new(value: T) -> Self {
         Wrapper { value }
     }
 }

exercises/intro/intro2.rs

@@ -6,5 +6,6 @@
 // hint.
 
 fn main() {
-    println!("Hello word!");
+    let world = "world!";
+    println!("Hello {}", world);
 }

exercises/iterators/iterators1.rs

@@ -9,17 +9,16 @@
 // Execute `rustlings hint iterators1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 fn main() {
     let my_fav_fruits = vec!["banana", "custard apple", "avocado", "peach", "raspberry"];
 
-    let mut my_iterable_fav_fruits = ???;   // TODO: Step 1
+    let mut my_iterable_fav_fruits = my_fav_fruits.iter();   // Step 1
 
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"banana"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 2
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"custard apple"));     // Step 2
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"avocado"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 3
+    assert_eq!(my_iterable_fav_fruits.next(), Some(&"peach"));     // Step 3
     assert_eq!(my_iterable_fav_fruits.next(), Some(&"raspberry"));
-    assert_eq!(my_iterable_fav_fruits.next(), ???);     // TODO: Step 4
+    assert_eq!(my_iterable_fav_fruits.next(), None);     // Step 4
 }

exercises/iterators/iterators2.rs

@@ -6,33 +6,41 @@
 // Execute `rustlings hint iterators2` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 // Step 1.
 // Complete the `capitalize_first` function.
 // "hello" -> "Hello"
 pub fn capitalize_first(input: &str) -> String {
     let mut c = input.chars();
-    match c.next() {
+    let result = match c.next() {
         None => String::new(),
-        Some(first) => ???,
-    }
+        Some(first) => first.to_uppercase().collect::<String>() + c.as_str(),
+    };
+    result
 }
 
 // Step 2.
 // Apply the `capitalize_first` function to a slice of string slices.
 // Return a vector of strings.
 // ["hello", "world"] -> ["Hello", "World"]
 pub fn capitalize_words_vector(words: &[&str]) -> Vec<String> {
-    vec![]
+    let mut s = vec![];
+    for word in words.iter() {
+        s.push(capitalize_first(word));
+    }
+    s
 }
 
 // Step 3.
 // Apply the `capitalize_first` function again to a slice of string slices.
 // Return a single string.
 // ["hello", " ", "world"] -> "Hello World"
 pub fn capitalize_words_string(words: &[&str]) -> String {
-    String::new()
+    let mut s = String::new();
+    for word in words.iter() {
+        s.push_str(&capitalize_first(word));
+    }
+    s
 }
 
 #[cfg(test)]

exercises/iterators/iterators3.rs

@@ -9,7 +9,6 @@
 // Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 #[derive(Debug, PartialEq, Eq)]
 pub enum DivisionError {
@@ -26,23 +25,31 @@ pub struct NotDivisibleError {
 // Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
-    todo!();
+    if b == 0 {
+        Err(DivisionError::DivideByZero)
+    } else if a % b != 0 {
+        Err(DivisionError::NotDivisible(NotDivisibleError {dividend:a, divisor:b}))
+    } else {
+        Ok(a / b)
+    }
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // Desired output: Ok([1, 11, 1426, 3])
-fn result_with_list() -> () {
+fn result_with_list() -> Result<Vec<i32>, DivisionError> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results : Result<Vec<_>,_> = numbers.into_iter().map(|n| divide(n, 27)).collect();
+    division_results
 }
 
 // Complete the function and return a value of the correct type so the test
 // passes.
 // Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
-fn list_of_results() -> () {
+fn list_of_results() -> Vec<Result<i32, DivisionError>> {
     let numbers = vec![27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results : Vec<Result<_,_>> = numbers.into_iter().map(|n| divide(n, 27)).collect();
+    division_results
 }
 
 #[cfg(test)]

exercises/iterators/iterators4.rs

@@ -3,9 +3,8 @@
 // Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-pub fn factorial(num: u64) -> u64 {
+pub fn factorial(n: u64) -> u64 {
     // Complete this function to return the factorial of num
     // Do not use:
     // - return
@@ -15,6 +14,9 @@ pub fn factorial(num: u64) -> u64 {
     // For an extra challenge, don't use:
     // - recursion
     // Execute `rustlings hint iterators4` for hints.
+
+    //(1..=n).product()
+    (1..=n).fold(1, |acc, x| acc * x)
 }
 
 #[cfg(test)]

exercises/iterators/iterators5.rs

@@ -11,7 +11,6 @@
 // Execute `rustlings hint iterators5` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
 use std::collections::HashMap;
 
@@ -35,7 +34,13 @@ fn count_for(map: &HashMap<String, Progress>, value: Progress) -> usize {
 fn count_iterator(map: &HashMap<String, Progress>, value: Progress) -> usize {
     // map is a hashmap with String keys and Progress values.
     // map = { "variables1": Complete, "from_str": None, ... }
-    todo!();
+    let mut c = 0;
+    for (_, p) in map.iter() {
+        if p == &value {
+            c += 1;
+        }
+    }
+    c
 }
 
 fn count_collection_for(collection: &[HashMap<String, Progress>], value: Progress) -> usize {
@@ -54,7 +59,15 @@ fn count_collection_iterator(collection: &[HashMap<String, Progress>], value: Pr
     // collection is a slice of hashmaps.
     // collection = [{ "variables1": Complete, "from_str": None, ... },
     //     { "variables2": Complete, ... }, ... ]
-    todo!();
+    let mut c = 0;
+    for i in collection {
+        for (_, p) in i.iter() {
+            if p == & value {
+                c += 1;
+            }
+        }
+    }
+    c
 }
 
 #[cfg(test)]

exercises/lifetimes/lifetimes1.rs

@@ -8,9 +8,8 @@
 // Execute `rustlings hint lifetimes1` or use the `hint` watch subcommand for a
 // hint.
 
-// I AM NOT DONE
 
-fn longest(x: &str, y: &str) -> &str {
+fn longest<'a> (x: &'a str, y: &'a str) -> &'a str {
     if x.len() > y.len() {
         x
     } else {