add rand, ordering, shadowing, type coercion

guessing_game/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+rand = "0.8.3"

guessing_game/src/main.rs

@@ -2,10 +2,15 @@
 // https://doc.rust-lang.org/std/prelude/index.html
 // for extras, import them with `use`:
 use std::io;
+use std::cmp::Ordering;
+use rand::Rng;
 
 fn main() {
     println!("Guess the number!");
     println!("input your guess");
+    // ..= is inclusive
+    let secret_number = rand::thread_rng().gen_range(1..=100);
+    println!("The secret number is: {secret_number}");
     // vars are immutable by default, change this
     // The :: syntax in the ::new line indicates that new is an _associated function_ of the String
     //         a function that’s implemented on a type
@@ -22,5 +27,17 @@ fn main() {
     // read_line returns a `result` value. result is an enum. Each possible state is a variant.
     // Result's variants are Ok and Err
 
+    // shadowing V
+    let guess: u32 = guess.trim().parse().expect("please type a number for the love of god");
+    // trim removes space and \n
     println!("you guessed: {guess}");
+    // a match expression is made of arms. an arm is a pattern to match and code to run against it.
+    // switch/case
+    match guess.cmp(&secret_number) {
+        Ordering::Less => println!("too small"),
+        Ordering::Greater => println!("too big"),
+        Ordering::Equal => println!("you win"),
+    }
 }
+// cargo doc --open
+// generate doc about this code and dependancies