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Merge pull request #19 from hoangph271/exercises/error_handling

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[Add] exercises/error_handling
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Snêu 2023-01-09 10:15:00 +07:00 committed by GitHub
commit 2d4db3e794
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4 changed files with 13 additions and 15 deletions
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2
exercises/error_handling/errors2.rs
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@ -24,7 +24,7 @@ pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
let cost_per_item = 5; 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) Ok(qty * cost_per_item + processing_fee)
} }
#[cfg(test)] #[cfg(test)]

11
exercises/error_handling/errors4.rs
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@ -1,8 +1,6 @@
// errors4.rs // errors4.rs
// Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint. // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
#[derive(PartialEq, Debug)] #[derive(PartialEq, Debug)]
struct PositiveNonzeroInteger(u64); struct PositiveNonzeroInteger(u64);
@ -14,8 +12,13 @@ enum CreationError {
impl PositiveNonzeroInteger { impl PositiveNonzeroInteger {
fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> { fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
// Hmm...? Why is this only returning an Ok value? // // Hmm...? Why is this only returning an Ok value?
Ok(PositiveNonzeroInteger(value as u64)) // Ok(PositiveNonzeroInteger(value as u64))
match value {
x if x < 0 => Err(CreationError::Negative),
0 => Err(CreationError::Zero),
_ => Ok(PositiveNonzeroInteger(value as u64))
}
} }
} }

4
exercises/error_handling/errors5.rs
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@ -16,14 +16,12 @@
// Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint. // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
use std::error; use std::error;
use std::fmt; use std::fmt;
use std::num::ParseIntError; use std::num::ParseIntError;
// TODO: update the return type of `main()` to make this compile. // 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 pretend_user_input = "42";
let x: i64 = pretend_user_input.parse()?; let x: i64 = pretend_user_input.parse()?;
println!("output={:?}", PositiveNonzeroInteger::new(x)?); println!("output={:?}", PositiveNonzeroInteger::new(x)?);

11
exercises/error_handling/errors6.rs
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@ -8,8 +8,6 @@
// Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint. // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
// I AM NOT DONE
use std::num::ParseIntError; use std::num::ParseIntError;
// This is a custom error type that we will be using in `parse_pos_nonzero()`. // This is a custom error type that we will be using in `parse_pos_nonzero()`.
@ -23,14 +21,13 @@ impl ParsePosNonzeroError {
fn from_creation(err: CreationError) -> ParsePosNonzeroError { fn from_creation(err: CreationError) -> ParsePosNonzeroError {
ParsePosNonzeroError::Creation(err) ParsePosNonzeroError::Creation(err)
} }
// TODO: add another error conversion function here. fn from_parseint (err: ParseIntError) -> ParsePosNonzeroError {
// fn from_parseint... ParsePosNonzeroError::ParseInt(err)
}
} }
fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> { fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
// TODO: change this to return an appropriate error instead of panicking let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
// when `parse()` returns an error.
let x: i64 = s.parse().unwrap();
PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation) PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
} }