errors option move semantics

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(format!("`name` was empty; it must be nonempty."))
     }
 }
 
@@ -27,7 +26,7 @@ mod tests {
     #[test]
     fn generates_nametag_text_for_a_nonempty_name() {
         assert_eq!(
-            generate_nametag_text("Beyoncé".into()),
+            generate_nametag_text("Beyoncé".into()).ok(),
             Some("Hi! My name is Beyoncé".into())
         );
     }

exercises/error_handling/errors2.rs

@@ -16,16 +16,15 @@
 // 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)
+    Ok(qty*cost_per_item + processing_fee)
 }
 
 #[cfg(test)]

exercises/error_handling/errors3.rs

@@ -4,7 +4,6 @@
 // Why not? What should we do to fix it?
 // Execute `rustlings hint errors3` for hints!
 
-// I AM NOT DONE
 
 use std::num::ParseIntError;
 
@@ -12,7 +11,7 @@ fn main() {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
-    let cost = total_cost(pretend_user_input)?;
+    let cost = total_cost(pretend_user_input).expect("wrong num");
 
     if cost > tokens {
         println!("You can't afford that many!");

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::new(num)?;
-    answer
+    Ok(answer)
 }
 
 // This is a test helper function that turns a &str into a BufReader.

exercises/move_semantics/move_semantics1.rs

@@ -1,12 +1,11 @@
 // move_semantics1.rs
 // Make me compile! Execute `rustlings hint move_semantics1` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
 
-    let vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(vec0);
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -15,7 +14,7 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: Vec<i32>) ->Vec<i32> {
     let mut vec = vec;
 
     vec.push(22);

exercises/move_semantics/move_semantics2.rs

@@ -2,12 +2,11 @@
 // Make me compile without changing line 13!
 // Execute `rustlings hint move_semantics2` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
     let vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec(&vec0);
 
     // Do not change the following line!
     println!("{} has length {} content `{:?}`", "vec0", vec0.len(), vec0);
@@ -17,8 +16,8 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(vec: &Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec = vec.clone();
 
     vec.push(22);
     vec.push(44);

exercises/move_semantics/move_semantics3.rs

@@ -3,10 +3,9 @@
 // (no lines with multiple semicolons necessary!)
 // Execute `rustlings hint move_semantics3` for hints :)
 
-// I AM NOT DONE
 
 fn main() {
-    let vec0 = Vec::new();
+    let mut vec0 = Vec::new();
 
     let mut vec1 = fill_vec(vec0);
 
@@ -17,7 +16,7 @@ fn main() {
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
+fn fill_vec(mut vec: Vec<i32>) -> Vec<i32> {
     vec.push(22);
     vec.push(44);
     vec.push(66);

exercises/move_semantics/move_semantics4.rs

@@ -4,12 +4,10 @@
 // freshly created vector from fill_vec to its caller.
 // Execute `rustlings hint move_semantics4` for hints!
 
-// I AM NOT DONE
 
 fn main() {
-    let vec0 = Vec::new();
 
-    let mut vec1 = fill_vec(vec0);
+    let mut vec1 = fill_vec();
 
     println!("{} has length {} content `{:?}`", "vec1", vec1.len(), vec1);
 
@@ -20,7 +18,7 @@ fn main() {
 
 // `fill_vec()` no longer take `vec: Vec<i32>` as argument
 fn fill_vec() -> Vec<i32> {
-    let mut vec = vec;
+    let mut vec : Vec<i32> = Vec::new();
 
     vec.push(22);
     vec.push(44);

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] = Default::default();
     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(value) = optional_values_vec.pop() {
-        println!("current value: {}", value);
+        println!("current value: {}", value.unwrap());
     }
 }