From ba9c08948d9bff06c4e64d0b463c45b0f67d876d Mon Sep 17 00:00:00 2001
From: Carson Rajcan <carajcan@gmail.com>
Date: Sun, 24 Jan 2021 15:48:31 -0600
Subject: [PATCH] Get to Generics
---
exercises/error_handling/errors1.rs | 11 ++++-------
exercises/error_handling/errors2.rs | 13 ++++++-------
exercises/error_handling/errors3.rs | 9 ++++++---
exercises/error_handling/errorsn.rs | 13 ++++++-------
exercises/move_semantics/move_semantics1.rs | 2 --
5 files changed, 22 insertions(+), 26 deletions(-)
diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index 9c24d85..e00e4e2 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -6,14 +6,11 @@
// 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, &'static str> {
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())
}
}
@@ -28,7 +25,7 @@ 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())
);
}
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index aad3a93..ad2870f 100644
--- a/exercises/error_handling/errors2.rs
+++ b/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;
+const PROCESSING_FEE: i32 = 1;
+const COST_PER_ITEM: i32 = 5;
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)
+ match item_quantity.parse::<i32>() {
+ Ok(qty) => Ok(qty * COST_PER_ITEM + PROCESSING_FEE),
+ error => error
+ }
}
#[cfg(test)]
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index 460ac5c..e6d9c3b 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -4,15 +4,18 @@
// 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() {
let mut tokens = 100;
let pretend_user_input = "8";
- let cost = total_cost(pretend_user_input)?;
+
+ let cost = match total_cost(pretend_user_input) {
+ Ok(cost) => cost,
+ Err(e) => return
+ };
+
if cost > tokens {
println!("You can't afford that many!");
diff --git a/exercises/error_handling/errorsn.rs b/exercises/error_handling/errorsn.rs
index 5fe212b..1e83b73 100644
--- a/exercises/error_handling/errorsn.rs
+++ b/exercises/error_handling/errorsn.rs
@@ -17,19 +17,18 @@
//
// 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);
- let num: i64 = line.trim().parse();
- let answer = PositiveNonzeroInteger::new(num);
- answer
+ b.read_line(&mut line)?;
+ let num: i64 = line.trim().parse()?;
+ let answer = PositiveNonzeroInteger::new(num)?;
+
+ Ok(answer)
}
//
diff --git a/exercises/move_semantics/move_semantics1.rs b/exercises/move_semantics/move_semantics1.rs
index 007a9f3..a95f851 100644
--- a/exercises/move_semantics/move_semantics1.rs
+++ b/exercises/move_semantics/move_semantics1.rs
@@ -1,8 +1,6 @@
// move_semantics1.rs
// Make me compile! Execute `rustlings hint move_semantics1` for hints :)
-// I AM NOT DONE
-
fn main() {
let vec0 = Vec::new();