Add conversions solutions

exercises/conversions/as_ref_mut.rs

@@ -2,17 +2,15 @@
 // Read more about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html
 // and https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
 
-// I AM NOT DONE
-
 // Obtain the number of bytes (not characters) in the given argument
 // Add the AsRef trait appropriately as a trait bound
-fn byte_counter<T>(arg: T) -> usize {
+fn byte_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().as_bytes().len()
 }
 
 // Obtain the number of characters (not bytes) in the given argument
 // Add the AsRef trait appropriately as a trait bound
-fn char_counter<T>(arg: T) -> usize {
+fn char_counter<T: AsRef<str>>(arg: T) -> usize {
     arg.as_ref().chars().count()
 }
 

exercises/conversions/from_into.rs

@@ -33,10 +33,20 @@ impl Default for Person {
 // If while parsing the age, something goes wrong, then return the default of Person
 // Otherwise, then return an instantiated Person object with the results
 
-// I AM NOT DONE
-
 impl From<&str> for Person {
     fn from(s: &str) -> Person {
+        let parts: Vec<_> = s.split(',').collect();
+
+        if parts.len() != 2 || parts[0] == "" {
+            Person::default()
+        } else {
+            let name = String::from(parts[0]);
+            if let Ok(age) = parts[1].parse() {
+                Person { name, age }
+            } else {
+                Person::default()
+            }
+        }
     }
 }
 

exercises/conversions/from_str.rs

@@ -10,8 +10,6 @@ struct Person {
     age: usize,
 }
 
-// I AM NOT DONE
-
 // Steps:
 // 1. If the length of the provided string is 0 an error should be returned
 // 2. Split the given string on the commas present in it
@@ -25,6 +23,20 @@ struct Person {
 impl FromStr for Person {
     type Err = String;
     fn from_str(s: &str) -> Result<Person, Self::Err> {
+        let parts: Vec<_> = s.split(',').collect();
+
+        if parts.len() != 2 {
+            Err(String::from("two parts expected but not provided"))
+        } else if parts[0] == "" {
+            Err(String::from("name must be non-empty"))
+        } else {
+            let name = String::from(parts[0]);
+            if let Ok(age) = parts[1].parse() {
+                Ok(Person { name, age })
+            } else {
+                Err(String::from("age must be a number"))
+            }
+        }
     }
 }
 

exercises/conversions/try_from_into.rs

@@ -11,8 +11,6 @@ struct Color {
     blue: u8,
 }
 
-// I AM NOT DONE
-
 // Your task is to complete this implementation
 // and return an Ok result of inner type Color.
 // You need to create an implementation for a tuple of three integers,
@@ -25,19 +23,49 @@ struct Color {
 // Tuple implementation
 impl TryFrom<(i16, i16, i16)> for Color {
     type Error = String;
-    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {}
+    fn try_from(tuple: (i16, i16, i16)) -> Result<Self, Self::Error> {
+        if let (Ok(red), Ok(green), Ok(blue)) =
+            (tuple.0.try_into(), tuple.1.try_into(), tuple.2.try_into())
+        {
+            Ok(Color { red, green, blue })
+        } else {
+            Err(String::from("one or more numbers are out of range (0-255)"))
+        }
+    }
 }
 
 // Array implementation
 impl TryFrom<[i16; 3]> for Color {
     type Error = String;
-    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {}
+    fn try_from(arr: [i16; 3]) -> Result<Self, Self::Error> {
+        if let (Ok(red), Ok(green), Ok(blue)) =
+            (arr[0].try_into(), arr[1].try_into(), arr[2].try_into())
+        {
+            Ok(Color { red, green, blue })
+        } else {
+            Err(String::from("one or more numbers are out of range (0-255)"))
+        }
+    }
 }
 
 // Slice implementation
 impl TryFrom<&[i16]> for Color {
     type Error = String;
-    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {}
+    fn try_from(slice: &[i16]) -> Result<Self, Self::Error> {
+        if slice.len() != 3 {
+            Err(String::from("incorrect slice length (expected 3 values)"))
+        } else {
+            if let (Ok(red), Ok(green), Ok(blue)) = (
+                slice[0].try_into(),
+                slice[1].try_into(),
+                slice[2].try_into(),
+            ) {
+                Ok(Color { red, green, blue })
+            } else {
+                Err(String::from("one or more numbers are out of range (0-255)"))
+            }
+        }
+    }
 }
 
 fn main() {

exercises/conversions/using_as.rs

@@ -5,11 +5,9 @@
 // The goal is to make sure that the division does not fail to compile
 // and returns the proper type.
 
-// I AM NOT DONE
-
 fn average(values: &[f64]) -> f64 {
     let total = values.iter().fold(0.0, |a, b| a + b);
-    total / values.len()
+    total / values.len() as f64
 }
 
 fn main() {