Small tweaks to things I wanted to change while reading through again

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Carol (Nichols || Goulding) 2016-08-16 17:10:03 -04:00
parent ed94e466db
commit b0126e2c97
2 changed files with 10 additions and 11 deletions

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@ -8,7 +8,7 @@ tradition.
> Note: This book assumes basic familiarity with the command line. Rust itself > Note: This book assumes basic familiarity with the command line. Rust itself
> makes no specific demands about your editing, tooling, or where your code > makes no specific demands about your editing, tooling, or where your code
> lives, so if you prefer an IDE to the command line, feel free to use your > lives, so if you prefer an IDE to the command line, feel free to use your
> favored IDE. > favorite IDE.
### Creating a Project File ### Creating a Project File

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@ -247,8 +247,8 @@ calls. Now let's see what this line does.
### Handling Potential Failure with the `Result` Type ### Handling Potential Failure with the `Result` Type
We mentioned that `read_line()` puts what the user types into the `&mut We mentioned that `read_line()` puts what the user types into the string we
String` we pass it, but it also returns a value: in this case, an pass it, but it also returns a value: in this case, an
[`io::Result`][ioresult]. Rust has a number of types named `Result` in its [`io::Result`][ioresult]. Rust has a number of types named `Result` in its
standard library: a generic [`Result`][result], and then specific versions for standard library: a generic [`Result`][result], and then specific versions for
sub-libraries, like `io::Result`. sub-libraries, like `io::Result`.
@ -305,7 +305,6 @@ brace:
```rust,ignore ```rust,ignore
println!("You guessed: {}", guess); println!("You guessed: {}", guess);
}
``` ```
This prints out the string we saved our input in. The `{}`s are a placeholder: This prints out the string we saved our input in. The `{}`s are a placeholder:
@ -744,9 +743,9 @@ let guess: u32 = guess.trim().parse()
We create a variable binding `guess`. But wait a minute, don't we already have We create a variable binding `guess`. But wait a minute, don't we already have
a variable binding named `guess`? We do, but Rust allows us to *shadow* the a variable binding named `guess`? We do, but Rust allows us to *shadow* the
previous value of `guess` with a new one. This is often used in this exact previous value of `guess` with a new one. This is often used in this exact
situation, where we want to convert a string to a numerical type. Shadowing situation, where we want to convert a value from one type into another type.
lets us re-use the `guess` variable name rather than forcing us to come up with Shadowing lets us re-use the `guess` variable name rather than forcing us to
two unique bindings, like `guess_str` and `guess` or something. come up with two unique bindings, like `guess_str` and `guess` or something.
We bind `guess` to the expression `guess.trim().parse()`. We bind `guess` to the expression `guess.trim().parse()`.
@ -760,9 +759,9 @@ represents "newline", the return key. The `trim()` method gets rid of this,
leaving our string with only the `5`. leaving our string with only the `5`.
The [`parse()` method on strings][parse] parses a string into some kind of The [`parse()` method on strings][parse] parses a string into some kind of
number. Since it can parse a variety of number types, we need to tell Rust the number. Since this method can parse a variety of number types, we need to tell
exact type of number we want with `let guess: u32`. The colon (`:`) after Rust the exact type of number we want with `let guess: u32`. The colon (`:`)
`guess` tells Rust were going to annotate its type. Rust has a few after `guess` tells Rust were going to annotate its type. Rust has a few
built-in number types, but weve chosen `u32`, an unsigned, thirty-two bit built-in number types, but weve chosen `u32`, an unsigned, thirty-two bit
integer. Its a good default choice for a small positive number. You'll see the integer. Its a good default choice for a small positive number. You'll see the
other number types in Chapter XX. other number types in Chapter XX.
@ -800,7 +799,7 @@ behavior with different kinds of input: guess the number correctly, guess a
number that is too high, and guess a number that is too low. number that is too high, and guess a number that is too low.
Now weve got most of the game working, but we can only make one guess. Lets Now weve got most of the game working, but we can only make one guess. Lets
change that by adding loops! change that by adding a loop!
## Allowing Multiple Guesses with Looping ## Allowing Multiple Guesses with Looping