started book again

book/guessing_game/src/main.rs

@@ -0,0 +1,12 @@
+use std::io;
+// file:///home/luket/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/share/doc/rust/html/std/io/index.html
+
+fn main() {
+    println!("guess the number");
+    println!("your guess: ");
+    let mut guess = String::new();
+    io::stdin()
+        .read_line(&mut guess)
+        .expect("failed to read line");
+    println!("your guess: {guess}");
+}