Obsidian/Zettelkasten/Hub Notes/Permanent Notes/Programming/Rust/Chapter 2 - Guessing Game.md

What we did:

Created a guessing game! This file takes in a number from the user, generates a random number, and compares the two to say whether the guess is correct, lower, or higher. It introduces us to key concepts in Rust such as module importing, the idea of mutability, how to define variables, and other interesting type things.

Breaking Down some things

Types, and variants

When creating the variable guess we created it as

let mut guess = String::new();

where we call String::new(). String is a type, that has a function new integrated into that type.

Then, we read in the data. Some interesting things happen here:

1. We use &mut guess where & signifies a reference to an object
2. We have an .expect() a. .read_line returns a string, but it also returns a result b. This result is an enumeration type, with each possible result being a variant.

Wacky stuff.

Next, we do some interesting things with strings. Printing strings uses curly brackets, kind of like python. These can hold the variable, or use an expression that is later in the print statement. Like this:

let x = 6;
let guess = 3;
println!("You guessed: {}, {x}", guess);

>> You guessed 3, 6 

Casting Types and Switching between ints and floats

Rust is particular about integers and floats. if something is u32, it will not infer switching to f32 when doing an operation between the two. Instead, an error is created. To deal with this, you have to use the 'as' command

let a: u32 = 1
let b: u32 = 2
let mut c: f32 = (a + b as f32)

The above code will work just fine.