Completes exercises

error_handling/errors1.rs

@@ -5,12 +5,11 @@
 // this function to have.
 // Scroll down for hints!!!
 
-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.".into())
     }
 }
 
@@ -25,7 +24,7 @@ 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())
         );
     }
 

error_handling/errors2.rs

@@ -20,9 +20,7 @@ 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>();
-
-    Ok(qty * cost_per_item + processing_fee)
+    item_quantity.parse::<i32>().map(|qty| qty * cost_per_item + processing_fee)
 }
 
 #[cfg(test)]

error_handling/errors3.rs

@@ -9,7 +9,7 @@ fn main() {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
-    let cost = try!(total_cost(pretend_user_input));
+    let cost = total_cost(pretend_user_input).expect("Invalid user input!");
 
     if cost > tokens {
         println!("You can't afford that many!");

error_handling/errorsn.rs

@@ -19,12 +19,12 @@ use std::fmt;
 use std::io;
 
 // PositiveNonzeroInteger is a struct defined below the tests.
-fn read_and_validate(b: &mut io::BufRead) -> Result<PositiveNonzeroInteger, ???> {
+fn read_and_validate(b: &mut io::BufRead) -> Result<PositiveNonzeroInteger, Box<error::Error>>{
     let mut line = String::new();
-    b.read_line(&mut line);
-    let num: i64 = line.trim().parse();
-    let answer = PositiveNonzeroInteger::new(num);
-    answer
+    try!(b.read_line(&mut line));
+    let num: i64 = try!(line.trim().parse());
+    let answer = try!(PositiveNonzeroInteger::new(num));
+    Ok(answer)
 }
 
 // This is a test helper function that turns a &str into a BufReader.

error_handling/option1.rs

@@ -6,11 +6,13 @@
 fn main() {
     let mut list = vec![3];
 
-    let last = list.pop().unwrap();
-    println!("The last item in the list is {:?}", last);
+    if let Some(last) = list.pop() {
+        println!("The last item in the list is {:?}", last);
+    }
 
-    let second_to_last = list.pop().unwrap();
-    println!("The second-to-last item in the list is {:?}", second_to_last);
+    if let Some(second_to_last) = list.pop() {
+        println!("The second-to-last item in the list is {:?}", second_to_last);
+    }
 }
 
 

error_handling/result1.rs

@@ -11,7 +11,11 @@ enum CreationError {
 
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
-        Ok(PositiveNonzeroInteger(value as u64))
+        match value {
+            0 => Err(CreationError::Zero),
+            _ if value < 0 => Err(CreationError::Negative),
+            _ => Ok(PositiveNonzeroInteger(value as u64))
+        }
     }
 }
 

ex1.rs

@@ -1,5 +1,5 @@
 // Make me compile!
 
 fn main() {
-    println();
+    println!();
 }

ex2.rs

@@ -1,7 +1,7 @@
 // Make me compile!
 
 fn something() -> String {
-    "hi!"
+    "hi!".into()
 }
 
 fn main() {

ex3.rs

@@ -1,5 +1,6 @@
 // Make me compile!
 
+#[derive(Debug)]
 struct Foo {
     capacity: i32,
 }

ex4.rs

@@ -1,7 +1,7 @@
 // Make me compile!
 
 fn something() -> Result<i32, std::num::ParseIntError> {
-    let x:i32 = "3".parse();
+    let x:i32 = try!("3".parse());
     Ok(x * 4)
 }
 

ex5.rs

@@ -5,17 +5,17 @@ enum Reaction<'a> {
     Happy(&'a str),
 }
 
-fn express(sentiment: Reaction) {
-    match sentiment {
+fn express(sentiment: &Reaction) {
+    match *sentiment {
         Reaction::Sad(s) => println!(":( {}", s),
         Reaction::Happy(s) => println!(":) {}", s),
     }
 }
 
 fn main () {
     let x = Reaction::Happy("It's a great day for Rust!");
-    express(x);
-    express(x);
+    express(&x);
+    express(&x);
     let y = Reaction::Sad("This code doesn't compile yet.");
-    express(y);
+    express(&y);
 }

functions/functions1.rs

@@ -4,6 +4,8 @@ fn main() {
     call_me();
 }
 
+fn call_me() { }
+
 
 
 

functions/functions2.rs

@@ -4,7 +4,7 @@ fn main() {
     call_me(3);
 }
 
-fn call_me(num) {
+fn call_me(num: i32) {
     for i in 0..num {
         println!("Ring! Call number {}", i + 1);
     }

functions/functions3.rs

@@ -1,7 +1,7 @@
 // Make me compile! Scroll down for hints :)
 
 fn main() {
-    call_me();
+    call_me(10);
 }
 
 fn call_me(num: i32) {

functions/functions4.rs

@@ -8,7 +8,7 @@ fn main() {
     println!("Your sale price is {}", sale_price(original_price));
 }
 
-fn sale_price(price: i32) -> {
+fn sale_price(price: i32) -> i32 {
     if is_even(price) {
         price - 10
     } else {

functions/functions5.rs

@@ -6,7 +6,7 @@ fn main() {
 }
 
 fn square(num: i32) -> i32 {
-    num * num;
+    num * num
 }
 
 

if/if1.rs

@@ -5,6 +5,11 @@ pub fn bigger(a: i32, b:i32) -> i32 {
     // - another function call
     // - additional variables
     // Scroll down for hints.
+    if a > b {
+        a
+    } else {
+        b
+    }
 }
 
 #[cfg(test)]

macros/macros1.rs

@@ -7,7 +7,7 @@ macro_rules! my_macro {
 }
 
 fn main() {
-    my_macro();
+    my_macro!();
 }
 
 

macros/macros2.rs

@@ -1,15 +1,16 @@
 // Make me compile! Scroll down for hints :)
 
-fn main() {
-    my_macro!();
-}
-
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
     };
 }
 
+fn main() {
+    my_macro!();
+}
+
+
 
 
 

macros/macros3.rs

@@ -1,5 +1,6 @@
 // Make me compile, without taking the macro out of the module! Scroll down for hints :)
 
+#[macro_use]
 mod macros {
     macro_rules! my_macro {
         () => {

macros/macros4.rs

@@ -3,7 +3,7 @@
 macro_rules! my_macro {
     () => {
         println!("Check out my macro!");
-    }
+    };
     ($val:expr) => {
         println!("Look at this other macro: {}", $val);
     }

modules/modules1.rs

@@ -1,7 +1,7 @@
 // Make me compile! Scroll down for hints :)
 
 mod sausage_factory {
-    fn make_sausage() {
+    pub fn make_sausage() {
         println!("sausage!");
     }
 }

modules/modules2.rs

@@ -1,8 +1,8 @@
 // Make me compile! Scroll down for hints :)
 
 mod us_presidential_frontrunners {
-    use self::democrats::HILLARY_CLINTON as democrat;
-    use self::republicans::DONALD_TRUMP as republican;
+    pub use self::democrats::HILLARY_CLINTON as democrat;
+    pub use self::republicans::DONALD_TRUMP as republican;
 
     mod democrats {
         pub const HILLARY_CLINTON: &'static str = "Hillary Clinton";
@@ -44,4 +44,4 @@ fn main() {
 // each constant.
 // One more hint: I wish the compiler error, instead of saying "unresolved name
 // `us_presidential_frontrunners::democrat`", could say  "constant
-// `us_presidential_frontrunners::democrat` is private"!
+// `us_presidential_frontrunners::democrat` is private"!

move_semantics/move_semantics1.rs

@@ -3,7 +3,7 @@
 pub 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);
 

move_semantics/move_semantics2.rs

@@ -3,7 +3,7 @@
 pub 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);
@@ -14,8 +14,8 @@ pub fn main() {
 
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+fn fill_vec(vec: &Vec<i32>) -> Vec<i32> {
+    let mut vec = vec.clone();
 
     vec.push(22);
     vec.push(44);

move_semantics/move_semantics3.rs

@@ -15,7 +15,7 @@ pub fn main() {
 
 }
 
-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);

move_semantics/move_semantics4.rs

@@ -3,9 +3,7 @@
 // freshly created vector from fill_vec to its caller. Scroll for hints!
 
 pub 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);
 
@@ -15,8 +13,8 @@ pub fn main() {
 
 }
 
-fn fill_vec(vec: Vec<i32>) -> Vec<i32> {
-    let mut vec = vec;
+fn fill_vec() -> Vec<i32> {
+    let mut vec = Vec::new();
 
     vec.push(22);
     vec.push(44);

primitive_types/primitive_types1.rs

@@ -9,7 +9,7 @@ fn main() {
         println!("Good morning!");
     }
 
-    let // Finish the rest of this line like the example! Or make it be false!
+    let is_evening = !is_morning; // Finish the rest of this line like the example! Or make it be false!
     if is_evening {
         println!("Good evening!");
     }

primitive_types/primitive_types2.rs

@@ -13,7 +13,7 @@ fn main() {
         println!("Neither alphabetic nor numeric!");
     }
 
-    let // Finish this line like the example! What's your favorite character?
+    let your_character = 'b';// Finish this line like the example! What's your favorite character?
     // Try a letter, try a number, try a special character, try a character
     // from a different language than your own, try an emoji!
     if your_character.is_alphabetic() {

primitive_types/primitive_types3.rs

@@ -1,8 +1,8 @@
-// Create an array with at least 100 elements in it where the ??? is. 
+// Create an array with at least 100 elements in it where the ??? is.
 // Scroll down for hints!
 
 fn main() {
-    let a = ???
+    let a = [0; 100];
 
     if a.len() >= 100 {
         println!("Wow, that's a big array!");
@@ -37,7 +37,7 @@ fn main() {
 
 
 
-// There's a shorthand to initialize Arrays with a certain size that does not 
+// There's a shorthand to initialize Arrays with a certain size that does not
 // require you to type in 100 items (but you certainly can if you want!)
 // Check out the Primitive Types -> Arrays section of the book:
 // http://doc.rust-lang.org/stable/book/primitive-types.html#arrays

primitive_types/primitive_types4.rs

@@ -4,7 +4,7 @@
 fn main() {
     let a = [1, 2, 3, 4, 5];
 
-    let nice_slice = ???
+    let nice_slice = &a[1..4];
 
     if nice_slice == [2, 3, 4] {
         println!("Nice slice!");

primitive_types/primitive_types5.rs

@@ -3,7 +3,7 @@
 
 fn main() {
     let cat = ("Furry McFurson", 3.5);
-    let /* your pattern here */ = cat;
+    let (name, age) = cat;
 
     println!("{} is {} years old.", name, age);
 }